diff --git a/changelog.d/fix-oh-medical-premium-lines.fixed.md b/changelog.d/fix-oh-medical-premium-lines.fixed.md
new file mode 100644
index 00000000000..02e7706f9f9
--- /dev/null
+++ b/changelog.d/fix-oh-medical-premium-lines.fixed.md
@@ -0,0 +1 @@
+Count Ohio health insurance premiums on the unreimbursed medical care worksheet: line 3 now takes premiums of anyone eligible for Medicare or an employer-paid plan (R.C. 5747.01(A)(10)), and line 1 reads the premium inputs the data fills, net of the federal self-employed health insurance deduction.
diff --git a/policyengine_us/tests/core/test_oh_unreimbursed_medical_deduction_invariants.py b/policyengine_us/tests/core/test_oh_unreimbursed_medical_deduction_invariants.py
index e1be0da4318..f14becb8240 100644
--- a/policyengine_us/tests/core/test_oh_unreimbursed_medical_deduction_invariants.py
+++ b/policyengine_us/tests/core/test_oh_unreimbursed_medical_deduction_invariants.py
@@ -6,14 +6,18 @@
 (premiums with no Medicare or employer plan, and long-term care premiums) are
 deducted in full. Each person carries their own lines 1 and 2 and a share of
 line 8 in proportion to their line 5 expenses, and Ohio AGI is the sum over
-the members.
+the members. Premiums go on line 1 if the person is eligible for neither
+Medicare nor a subsidized plan of the taxpayer's or spouse's employer
+(R.C. 5747.01(A)(10)(a)), and on line 3, part of line 5, otherwise.
 
 Hypothesis draws batches of tax units (single, joint, head of household or
-joint with dependents), each person with wages, medical expenses, uninsured
-premiums and long-term care premiums, and some heads with a business loss
-that makes federal AGI negative. A seeded population of 200 units adds
-breadth. Each batch runs as one vectorized simulation, and again with every
-medical amount set to zero. For every tax unit:
+joint with dependents), each person with wages, medical expenses, health
+insurance premiums, long-term care premiums, Medicare eligibility, employer
+coverage, an employer coverage offer and an employer contribution category,
+and some heads with a business loss that makes federal AGI negative. A seeded
+population of 200 units adds breadth. Each batch runs as one vectorized
+simulation, and again with every medical amount set to zero. For every tax
+unit:
 
 1. Conservation: the members' line 8 shares sum to the return's line 8.
 2. Differential: line 8 and each share equal an independent numpy worksheet,
@@ -25,6 +29,11 @@
    deduction, and raises each person's Ohio AGI (and joint filing credit
    qualifying income) by exactly their own share, so a spouse never loses
    qualifying income for the other spouse's expenses.
+5. Partition: each person's premiums are on exactly one of lines 1 and 3, so
+   line 1 plus the premiums on line 3 equals the premiums paid. Line 1 is
+   zero for everyone on a return where the head or spouse has employer
+   coverage, an offer of it, or an employer paying some or all of their
+   premiums, and for every Medicare-eligible person.
 """
 
 import numpy as np
@@ -48,6 +57,12 @@
     "health_insurance_premiums",
     "long_term_health_insurance_premiums",
 ]
+COVERAGE = [
+    "is_medicare_eligible",
+    "has_esi",
+    "offered_aca_disqualifying_esi",
+    "employer_contribution_to_health_insurance_premiums_category",
+]
 
 amounts = st.one_of(
     st.just(0.0),
@@ -56,6 +71,10 @@
 )
 wages = st.one_of(st.just(0.0), st.integers(1, 200_000).map(float))
 losses = st.one_of(st.just(0.0), st.integers(-100_000, -1).map(float))
+# Weighted toward the defaults: no Medicare, no employer coverage and the NONE
+# category, which says nothing about whether an employer plan exists.
+CATEGORIES = ["NONE", "NONE", "NONE", "SOME", "ALL", "NA"]
+rare = st.sampled_from([False, False, False, True])
 
 
 @st.composite
@@ -65,6 +84,12 @@ def people(draw):
         "other_medical_expenses": draw(amounts),
         "health_insurance_premiums": draw(amounts),
         "long_term_health_insurance_premiums": draw(amounts),
+        "is_medicare_eligible": draw(rare),
+        "has_esi": draw(rare),
+        "offered_aca_disqualifying_esi": draw(rare),
+        "employer_contribution_to_health_insurance_premiums_category": draw(
+            st.sampled_from(CATEGORIES)
+        ),
     }
 
 
@@ -97,6 +122,12 @@ def person():
             "other_medical_expenses": amount(),
             "health_insurance_premiums": amount(),
             "long_term_health_insurance_premiums": amount(),
+            "is_medicare_eligible": bool(rng.random() < 0.25),
+            "has_esi": bool(rng.random() < 0.25),
+            "offered_aca_disqualifying_esi": bool(rng.random() < 0.25),
+            "employer_contribution_to_health_insurance_premiums_category": str(
+                rng.choice(CATEGORIES)
+            ),
         }
 
     units = []
@@ -121,14 +152,15 @@ def _situation(units, year, *, medical):
 
     def add(name, values, role):
         people[name] = {
-            # Under 65 and not disabled, so no one is eligible for Medicare
-            # and worksheet line 3 is zero.
             "age": {"head": 45, "spouse": 43, "dependent": 10}[role],
             "is_tax_unit_head": role == "head",
             "is_tax_unit_spouse": role == "spouse",
             "is_tax_unit_dependent": role == "dependent",
             "employment_income": values["employment_income"],
-            "employer_contribution_to_health_insurance_premiums_category": "NONE",
+            **{name: values[name] for name in COVERAGE},
+            # No modeled Medicare Part B premium, so the premiums are only
+            # the drawn ones and zeroing them removes every medical amount.
+            "takes_up_medicare_if_eligible": False,
             **{name: values[name] * medical for name in MEDICAL},
         }
 
@@ -162,6 +194,11 @@ def add(name, values, role):
 
 PERSON = [
     "other_medical_expenses",
+    "health_insurance_premiums",
+    "oh_medical_care_insurance_premiums",
+    "is_medicare_eligible",
+    "has_esi",
+    "offered_aca_disqualifying_esi",
     "oh_insured_unreimbursed_medical_care_expense_amount",
     "oh_insured_unreimbursed_medical_care_expenses_person",
     "oh_uninsured_unreimbursed_medical_care_expenses",
@@ -172,6 +209,7 @@ def add(name, values, role):
 ]
 TAX_UNIT = [
     "adjusted_gross_income",
+    "oh_employer_subsidized_health_plan_eligible",
     "oh_insured_unreimbursed_medical_care_expenses",
     "oh_unreimbursed_medical_care_expense_deduction",
     "oh_agi",
@@ -185,6 +223,9 @@ def _run(units, year, *, medical=True):
         for name in PERSON + TAX_UNIT
     }
     out["filer"] = np.asarray(sim.calculate("is_tax_unit_head_or_spouse", year))
+    out["category"] = sim.calculate(
+        "employer_contribution_to_health_insurance_premiums_category", year
+    ).decode_to_str()
     out["unit"] = sim.populations["tax_unit"].members_entity_id
     return out
 
@@ -199,11 +240,28 @@ def _check(units, year):
     line_5_person = base["oh_insured_unreimbursed_medical_care_expense_amount"]
     line_8 = base["oh_insured_unreimbursed_medical_care_expenses"]
     share = base["oh_insured_unreimbursed_medical_care_expenses_person"]
+    line_1 = base["oh_uninsured_unreimbursed_medical_care_expenses"]
 
-    # No one is Medicare eligible, so line 5 is each person's medical care.
+    # 5. Partition, against an independent reading of the worksheet. No one
+    # is self-employed, so the premiums are the drawn ones.
+    premiums = base["health_insurance_premiums"]
     np.testing.assert_allclose(
-        line_5_person, base["other_medical_expenses"], atol=TOLERANCE
+        base["oh_medical_care_insurance_premiums"], premiums, atol=TOLERANCE
+    )
+    employer_plan = (
+        (base["has_esi"] > 0)
+        | (base["offered_aca_disqualifying_esi"] > 0)
+        | np.isin(base["category"], ["SOME", "ALL"])
     )
+    return_eligible = _unit_sum(base, base["filer"] * employer_plan) > 0
+    np.testing.assert_array_equal(
+        base["oh_employer_subsidized_health_plan_eligible"] > 0, return_eligible
+    )
+    on_line_3 = (base["is_medicare_eligible"] > 0) | return_eligible[unit]
+    line_3 = line_5_person - base["other_medical_expenses"]
+    np.testing.assert_allclose(line_1, np.where(on_line_3, 0, premiums), atol=TOLERANCE)
+    np.testing.assert_allclose(line_3, np.where(on_line_3, premiums, 0), atol=TOLERANCE)
+    np.testing.assert_allclose(line_1 + line_3, premiums, atol=TOLERANCE)
     line_5 = _unit_sum(base, line_5_person)
 
     # 1. Conservation.
@@ -250,13 +308,20 @@ def _check(units, year):
     np.testing.assert_allclose(
         without["oh_unreimbursed_medical_care_expense_deduction"], 0, atol=TOLERANCE
     )
-    np.testing.assert_allclose(
-        without["oh_agi"] - base["oh_agi"], deduction, atol=TOLERANCE
-    )
+    _assert_difference(without["oh_agi"], base["oh_agi"], deduction, "oh_agi")
     for name in ["oh_agi_person", "oh_joint_filing_credit_qualifying_income"]:
-        np.testing.assert_allclose(
-            without[name] - base[name], person_deduction, atol=TOLERANCE, err_msg=name
-        )
+        _assert_difference(without[name], base[name], person_deduction, name)
+
+
+def _assert_difference(minuend, subtrahend, expected, name):
+    # Incomes are float32, so above 131,072 the spacing between values is
+    # 0.016 or more, and a difference of two incomes is only exact to about
+    # one spacing of the larger.
+    spacing = np.spacing(
+        np.maximum(np.abs(minuend), np.abs(subtrahend)).astype(np.float32)
+    )
+    error = np.abs(minuend - subtrahend - expected)
+    assert (error <= TOLERANCE + 2 * spacing).all(), name
 
 
 # A batch's cost is mostly per-variable overhead, so each example is a large
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/integration.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/integration.yaml
index 738c898e2d0..2ac9114478a 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/integration.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/integration.yaml
@@ -20,7 +20,9 @@
     other_medical_expenses: 600
     employer_contribution_to_health_insurance_premiums_category: "SOME"
   output:
-    oh_insured_unreimbursed_medical_care_expenses: 0
+    # Medicare eligible, so the premiums are on line 3 whatever the employer
+    # paid: 500 + 600 - 10,000 * 7.5% = 350.
+    oh_insured_unreimbursed_medical_care_expenses: 350
 
 - name: moop > agi * rate
   period: 2022
@@ -106,5 +108,7 @@
         members: [head, spouse]
         state_code: OH
   output:
-    oh_insured_unreimbursed_medical_care_expenses: 950 
+    # Both are Medicare eligible, so both spouses' premiums are on line 3:
+    # 300 + 500 + 200 + 300 - 2,000 * 7.5% = 1,150.
+    oh_insured_unreimbursed_medical_care_expenses: 1_150 
 
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.yaml
index 3ddeb38614e..928bbe7e150 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.yaml
@@ -9,7 +9,9 @@
   output:
     oh_insured_unreimbursed_medical_care_expense_amount: 1_100
 
-- name: Medicare ineligible with moop
+- name: Medicare eligible with an employer-paid plan and moop
+  # Line 3 takes premiums of anyone eligible for Medicare or an employer-paid
+  # plan, so an employer paying part of the premium does not remove them.
   period: 2022
   input:
     state_code: OH
@@ -18,9 +20,9 @@
     other_medical_expenses: 600
     employer_contribution_to_health_insurance_premiums_category: "SOME"
   output:
-    oh_insured_unreimbursed_medical_care_expense_amount: 600
+    oh_insured_unreimbursed_medical_care_expense_amount: 1_100
 
-- name: Medicare ineligible without moop
+- name: Medicare eligible with an employer-paid plan and no moop
   period: 2022
   input:
     state_code: OH
@@ -29,4 +31,71 @@
     other_medical_expenses: 0
     employer_contribution_to_health_insurance_premiums_category: "SOME"
   output:
-    oh_insured_unreimbursed_medical_care_expense_amount: 0
+    oh_insured_unreimbursed_medical_care_expense_amount: 500
+
+# Worksheet line 3 (2025 instructions, p. 41): premiums paid while "eligible
+# for Medicare or an employer-paid health care plan through your or your
+# spouse's employer", added to line 4 medical care, R.C. 5747.01(A)(10)(b).
+
+- name: After-tax premiums of a person with employer coverage count on line 3
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 45
+        has_esi: true
+        employment_income: 60_000
+        health_insurance_premiums_without_medicare_part_b: 6_500
+        other_medical_expenses: 800
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    oh_insured_unreimbursed_medical_care_expense_amount: 7_300
+
+- name: Premiums with no Medicare or employer plan go to line 1, not line 3
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 45
+        employment_income: 60_000
+        health_insurance_premiums_without_medicare_part_b: 6_000
+        other_medical_expenses: 500
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    oh_insured_unreimbursed_medical_care_expense_amount: 500
+    oh_uninsured_unreimbursed_medical_care_expenses: 6_000
+
+- name: Premiums paid through pre-tax payroll deductions are not deducted
+  # Line 44 instructions (p. 26) and FAQ Q2: no deduction for amounts paid
+  # with pre-tax dollars. They are excluded from federal wages instead.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 45
+        has_esi: true
+        employment_income: 60_000
+        pre_tax_health_insurance_premiums: 2_000
+        other_medical_expenses: 500
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    irs_employment_income: 58_000
+    oh_insured_unreimbursed_medical_care_expense_amount: 500
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_employer_subsidized_health_plan_eligible.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_employer_subsidized_health_plan_eligible.yaml
new file mode 100644
index 00000000000..bf0205f82c4
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_employer_subsidized_health_plan_eligible.yaml
@@ -0,0 +1,102 @@
+# R.C. 5747.01(A)(10)(a) bars the full premium deduction for "any taxpayer who
+# is eligible to participate in any subsidized health plan maintained by any
+# employer of the taxpayer or of the taxpayer's spouse". The 2025 worksheet
+# (p. 41) asks whether "you" were eligible for "an employer-paid health care
+# plan through your or your spouse's employer".
+
+- name: Head with employer coverage
+  period: 2025
+  input:
+    people:
+      head:
+        has_esi: true
+      spouse:
+        has_esi: false
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: OH
+  output:
+    oh_employer_subsidized_health_plan_eligible: true
+
+- name: Spouse with employer coverage makes the return eligible
+  period: 2025
+  input:
+    people:
+      head:
+        has_esi: false
+      spouse:
+        has_esi: true
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: OH
+  output:
+    oh_employer_subsidized_health_plan_eligible: true
+
+- name: Offer of employer coverage the filer declined
+  period: 2025
+  input:
+    state_code: OH
+    offered_aca_disqualifying_esi: true
+  output:
+    oh_employer_subsidized_health_plan_eligible: true
+
+- name: Employer pays some of the filer's premiums
+  period: 2025
+  input:
+    state_code: OH
+    employer_contribution_to_health_insurance_premiums_category: SOME
+  output:
+    oh_employer_subsidized_health_plan_eligible: true
+
+- name: Employer pays all of the filer's premiums
+  period: 2025
+  input:
+    state_code: OH
+    employer_contribution_to_health_insurance_premiums_category: ALL
+  output:
+    oh_employer_subsidized_health_plan_eligible: true
+
+- name: Employer pays none of the premiums and no employer coverage
+  period: 2025
+  input:
+    state_code: OH
+    employer_contribution_to_health_insurance_premiums_category: NONE
+  output:
+    oh_employer_subsidized_health_plan_eligible: false
+
+- name: Employer contribution not applicable
+  period: 2025
+  input:
+    state_code: OH
+    employer_contribution_to_health_insurance_premiums_category: NA
+  output:
+    oh_employer_subsidized_health_plan_eligible: false
+
+- name: Only a dependent has employer coverage
+  period: 2025
+  input:
+    people:
+      head:
+        age: 50
+      child:
+        age: 20
+        is_tax_unit_dependent: true
+        has_esi: true
+        employer_contribution_to_health_insurance_premiums_category: SOME
+    tax_units:
+      tax_unit:
+        members: [head, child]
+    households:
+      household:
+        members: [head, child]
+        state_code: OH
+  output:
+    oh_employer_subsidized_health_plan_eligible: false
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_medical_care_insurance_premiums.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_medical_care_insurance_premiums.yaml
new file mode 100644
index 00000000000..36c1c46fd9c
--- /dev/null
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_medical_care_insurance_premiums.yaml
@@ -0,0 +1,53 @@
+# Dental, vision and health insurance premiums the taxpayer paid, for
+# worksheet lines 1 and 3 (2025 instructions, p. 41), to the extent not
+# otherwise deducted or excluded in computing federal AGI
+# (R.C. 5747.01(A)(10)(a)-(b)).
+
+- name: Direct premium input
+  period: 2025
+  input:
+    state_code: OH
+    health_insurance_premiums: 3_000
+  output:
+    oh_medical_care_insurance_premiums: 3_000
+
+- name: Non-Medicare premiums are counted once, not with the SPM component
+  period: 2025
+  input:
+    state_code: OH
+    age: 40
+    health_insurance_premiums_without_medicare_part_b: 6_500
+    other_health_insurance_premiums: 6_500
+    employer_sponsored_insurance_premiums: 20_000
+  output:
+    oh_medical_care_insurance_premiums: 6_500
+
+- name: Premiums paid through pre-tax payroll deductions are left out
+  period: 2025
+  input:
+    state_code: OH
+    employment_income: 50_000
+    pre_tax_health_insurance_premiums: 2_000
+  output:
+    oh_medical_care_insurance_premiums: 0
+
+- name: Premiums deducted as self-employed health insurance are left out
+  period: 2025
+  input:
+    state_code: OH
+    is_self_employed: true
+    self_employment_income: 3_000
+    health_insurance_premiums: 5_000
+  output:
+    # 5,000 - min(3,000, 5,000).
+    oh_medical_care_insurance_premiums: 2_000
+
+- name: The self-employed deduction cannot make premiums negative
+  period: 2025
+  input:
+    state_code: OH
+    is_self_employed: true
+    self_employment_income: 80_000
+    health_insurance_premiums: 5_000
+  output:
+    oh_medical_care_insurance_premiums: 0
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_uninsured_unreimbursed_medical_care_expenses.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_uninsured_unreimbursed_medical_care_expenses.yaml
index 413b070a4fe..d9eac668dff 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_uninsured_unreimbursed_medical_care_expenses.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_uninsured_unreimbursed_medical_care_expenses.yaml
@@ -27,3 +27,174 @@
     employer_contribution_to_health_insurance_premiums_category: "ALL"
   output:
     oh_uninsured_unreimbursed_medical_care_expenses: 0
+
+# Worksheet line 1 (2025 instructions, p. 41): premiums paid while "not
+# eligible for Medicare or an employer-paid health care plan through your or
+# your spouse's employer", R.C. 5747.01(A)(10)(a).
+
+- name: Premiums reported as non-Medicare premiums count on line 1
+  # Microdata and most household inputs report premiums through
+  # health_insurance_premiums_without_medicare_part_b, not the direct input.
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+        employment_income: 50_000
+        health_insurance_premiums_without_medicare_part_b: 6_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: 6_000
+
+- name: The spouse's employer plan moves the head's private premiums off line 1
+  # Ohio FAQ Q9: a taxpayer who declines the spouse's employer plan and buys
+  # private insurance enters those premiums on line 3.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 40
+        health_insurance_premiums_without_medicare_part_b: 4_000
+      spouse:
+        age: 38
+        has_esi: true
+        employment_income: 50_000
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+    marital_units:
+      marital_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: [0, 0]
+    oh_insured_unreimbursed_medical_care_expense_amount: [4_000, 0]
+    # Line 8 = 4,000 - 0.075 * 50,000 = 250.
+    oh_unreimbursed_medical_care_expense_deduction: 250
+
+- name: A dependent's premiums follow the filer's employer plan
+  period: 2025
+  input:
+    people:
+      head:
+        age: 40
+        has_esi: true
+        employment_income: 50_000
+      child:
+        age: 10
+        is_tax_unit_dependent: true
+        health_insurance_premiums_without_medicare_part_b: 1_000
+    tax_units:
+      tax_unit:
+        members: [head, child]
+    households:
+      household:
+        members: [head, child]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: [0, 0]
+    oh_insured_unreimbursed_medical_care_expense_amount: [0, 1_000]
+
+- name: A dependent's own employer coverage does not bar the filer's line 1
+  # The bar is a plan "maintained by any employer of the taxpayer or of the
+  # taxpayer's spouse"; a dependent's employer is neither.
+  period: 2025
+  input:
+    people:
+      head:
+        age: 50
+        employment_income: 50_000
+        health_insurance_premiums_without_medicare_part_b: 3_000
+      child:
+        age: 20
+        is_tax_unit_dependent: true
+        is_full_time_student: true
+        has_esi: true
+    tax_units:
+      tax_unit:
+        members: [head, child]
+    households:
+      household:
+        members: [head, child]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: [3_000, 0]
+
+- name: An offer of employer coverage the filer declined still bars line 1
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+        employment_income: 50_000
+        offered_aca_disqualifying_esi: true
+        health_insurance_premiums_without_medicare_part_b: 5_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: 0
+    oh_insured_unreimbursed_medical_care_expense_amount: 5_000
+
+- name: Only the Medicare-eligible spouse's premiums leave line 1
+  period: 2025
+  input:
+    people:
+      head:
+        age: 66
+        is_medicare_eligible: true
+        health_insurance_premiums: 2_000
+      spouse:
+        age: 60
+        is_medicare_eligible: false
+        health_insurance_premiums_without_medicare_part_b: 3_000
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+    marital_units:
+      marital_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: OH
+  output:
+    oh_uninsured_unreimbursed_medical_care_expenses: [0, 3_000]
+    oh_insured_unreimbursed_medical_care_expense_amount: [2_000, 0]
+
+- name: Line 1 is reduced by the federal self-employed health insurance deduction
+  # Worksheet line 1 note: "You must reduce the amount you enter on this line
+  # by your federal self-employed health insurance deduction".
+  period: 2025
+  input:
+    people:
+      person1:
+        age: 40
+        is_self_employed: true
+        self_employment_income: 3_000
+        health_insurance_premiums: 5_000
+    tax_units:
+      tax_unit:
+        members: [person1]
+    households:
+      household:
+        members: [person1]
+        state_code: OH
+  output:
+    # min(3,000 of earnings, 5,000 of premiums).
+    self_employed_health_insurance_ald: 3_000
+    # 5,000 - 3,000.
+    oh_uninsured_unreimbursed_medical_care_expenses: 2_000
diff --git a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_unreimbursed_medical_care_expense_deduction.yaml b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_unreimbursed_medical_care_expense_deduction.yaml
index 5691fa861dc..e0016b82f27 100644
--- a/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_unreimbursed_medical_care_expense_deduction.yaml
+++ b/policyengine_us/tests/policy/baseline/gov/states/oh/tax/income/deductions/medical_expense/oh_unreimbursed_medical_care_expense_deduction.yaml
@@ -143,3 +143,69 @@
     # tax 342 + 2.75% * (52,350 - 26,050) = 1,065.25 (2025 instructions, p. 18).
     # MAGI less exemptions is 52,350, so the credit is 10% = 106.53.
     oh_joint_filing_credit: 106.53
+
+- name: PolicyBench scenario_025, after-tax premiums of a spouse with employer coverage count on line 3
+  # R.C. 5747.01(A)(10)(a) bars the full premium deduction (worksheet line 1)
+  # for a taxpayer eligible for a subsidized plan of the taxpayer's or the
+  # spouse's employer. Division (b) still counts premiums the taxpayer paid,
+  # not otherwise deducted or excluded, toward medical care above 7.5% of
+  # federal AGI. The 2025 worksheet (p. 41) puts them on line 3, for anyone
+  # "eligible for Medicare or an employer-paid health care plan", and Ohio's
+  # FAQ (Q8) says the same of after-tax premiums for an employer plan. The
+  # inputs are PolicyBench scenario_025's; it previously deducted nothing.
+  period: 2026
+  absolute_error_margin: 0.01
+  input:
+    people:
+      head:
+        age: 61
+        has_esi: true
+        hours_worked_last_week: 40
+        health_insurance_premiums_without_medicare_part_b: 6_500
+        # The same 6,500 under the SPM premium decomposition; not added again.
+        other_health_insurance_premiums: 6_500
+        # Employer-paid, excluded from income under IRC 106, so not paid by
+        # the taxpayer.
+        employer_sponsored_insurance_premiums: 21_207.525390625
+        other_medical_expenses: 800
+        # Not prescribed drugs, so not medical care under IRC 213(b).
+        over_the_counter_health_expenses: 50
+      spouse:
+        age: 57
+        has_esi: true
+        employment_income: 62_725.29296875
+        taxable_private_pension_income: 32_200
+        hourly_wage: 19.450000762939453
+        hours_worked_last_week: 40
+        is_paid_hourly: true
+        bank_account_assets: 54_394.1171875
+    tax_units:
+      tax_unit:
+        members: [head, spouse]
+        first_home_mortgage_balance: 366_000
+    marital_units:
+      marital_unit:
+        members: [head, spouse]
+    households:
+      household:
+        members: [head, spouse]
+        state_code: OH
+        household_vehicles_value: 9_510
+  output:
+    # 62,725.29 + 32,200.
+    adjusted_gross_income: 94_925.29
+    # Line 1: barred by the employer plan.
+    oh_uninsured_unreimbursed_medical_care_expenses: [0, 0]
+    # Line 3 (6,500) + line 4 (800).
+    oh_insured_unreimbursed_medical_care_expense_amount: [7_300, 0]
+    # Line 8 = 7,300 - 0.075 * 94,925.29 = 7,300 - 7,119.40 = 180.60.
+    oh_insured_unreimbursed_medical_care_expenses: 180.60
+    oh_unreimbursed_medical_care_expense_deduction: 180.60
+    # 94,925.29 - 180.60.
+    oh_agi: 94_744.69
+    # Less 2 * 1,900 exemptions (MAGI above 80,000; R.C. 5747.025).
+    oh_taxable_income: 90_944.69
+    # R.C. 5747.02(A) for 2026: 332 + 2.75% * (90,944.69 - 26,050) = 2,116.60,
+    # less the 200 retirement income credit (R.C. 5747.055(B)). Was 1,921.57.
+    oh_income_tax_before_refundable_credits: 1_916.60
+    state_income_tax_before_refundable_credits: 1_916.60
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.py
index b7adead891b..fac1790799c 100644
--- a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.py
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expense_amount.py
@@ -8,25 +8,22 @@ class oh_insured_unreimbursed_medical_care_expense_amount(Variable):
     unit = USD
     definition_period = YEAR
     reference = (
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=18",  # Line 36
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=27",
-        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(10)
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)(b)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=25",  # Line 44, pp. 25-26
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet lines 3 and 4
+        "https://tax.ohio.gov/help-center/faqs/income-medical-and-health-care-expenses/income-medical-and-health-care-expenses",  # Q8 and Q9: after-tax premiums go on line 3
     )
     defined_for = StateCode.OH
 
     def formula(person, period, parameters):
-        employer_premium_contribution = person(
-            "employer_contribution_to_health_insurance_premiums_category",
-            period,
-        )
-        status = employer_premium_contribution.possible_values
+        premiums = person("oh_medical_care_insurance_premiums", period)
         medicare_eligible = person("is_medicare_eligible", period)
-        # Line 3
-        eligible_premiums = (
-            person("medical_expense_health_insurance_premiums", period)
-            * medicare_eligible
-        ) * (employer_premium_contribution == status.NONE)
-        # Premiums only count if the employer paid none.
+        employer_plan_eligible = person.tax_unit(
+            "oh_employer_subsidized_health_plan_eligible", period
+        )
+        # Line 3: premiums paid while eligible for Medicare or an
+        # employer-paid plan.
+        eligible_premiums = premiums * (medicare_eligible | employer_plan_eligible)
         # Line 4
         other_medical_expenses = person("other_medical_expenses", period)
         return eligible_premiums + other_medical_expenses
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expenses_person.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expenses_person.py
index 03d07755a80..6386719ef97 100644
--- a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expenses_person.py
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/insured_unreimbursed_expenses/oh_insured_unreimbursed_medical_care_expenses_person.py
@@ -8,9 +8,9 @@ class oh_insured_unreimbursed_medical_care_expenses_person(Variable):
     unit = USD
     definition_period = YEAR
     reference = (
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=18",  # Line 36
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=27",
-        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(10)
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=25",  # Line 44, pp. 25-26
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet
     )
     defined_for = StateCode.OH
 
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_employer_subsidized_health_plan_eligible.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_employer_subsidized_health_plan_eligible.py
new file mode 100644
index 00000000000..fa6ae208be7
--- /dev/null
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_employer_subsidized_health_plan_eligible.py
@@ -0,0 +1,30 @@
+from policyengine_us.model_api import *
+
+
+class oh_employer_subsidized_health_plan_eligible(Variable):
+    value_type = bool
+    entity = TaxUnit
+    label = "Ohio filer eligible for an employer-subsidized health plan"
+    definition_period = YEAR
+    reference = (
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)(a)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet lines 1 and 3
+    )
+    defined_for = StateCode.OH
+
+    def formula(tax_unit, period, parameters):
+        person = tax_unit.members
+        # Enrolled in, or offered, employer coverage.
+        has_employer_coverage = person("has_esi", period) | person(
+            "offered_aca_disqualifying_esi", period
+        )
+        contribution = person(
+            "employer_contribution_to_health_insurance_premiums_category",
+            period,
+        )
+        status = contribution.possible_values
+        employer_pays = (contribution == status.SOME) | (contribution == status.ALL)
+        # The plan must be maintained by the taxpayer's or the spouse's
+        # employer, so a dependent's own coverage does not count.
+        head_or_spouse = person("is_tax_unit_head_or_spouse", period)
+        return tax_unit.any(head_or_spouse & (has_employer_coverage | employer_pays))
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_medical_care_insurance_premiums.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_medical_care_insurance_premiums.py
new file mode 100644
index 00000000000..3094d5705a6
--- /dev/null
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_medical_care_insurance_premiums.py
@@ -0,0 +1,27 @@
+from policyengine_us.model_api import *
+
+
+class oh_medical_care_insurance_premiums(Variable):
+    value_type = float
+    entity = Person
+    label = "Ohio medical care insurance premiums for the unreimbursed medical care deduction"
+    unit = USD
+    definition_period = YEAR
+    reference = (
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)(a)-(b)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=25",  # Line 44, pp. 25-26
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet lines 1 and 3
+    )
+    defined_for = StateCode.OH
+
+    def formula(person, period, parameters):
+        # Premiums counted as IRC 213 medical care, as in the federal medical
+        # expense deduction. Premiums paid through pre-tax payroll deductions
+        # are a separate input, excluded from wages, so they are not included.
+        premiums = person("medical_expense_health_insurance_premiums", period)
+        # Premiums already deducted in computing federal AGI are not deducted
+        # again (worksheet line 1 note).
+        self_employed_deduction = person(
+            "self_employed_health_insurance_ald_person", period
+        )
+        return max_(premiums - self_employed_deduction, 0)
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_uninsured_unreimbursed_medical_care_expenses.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_uninsured_unreimbursed_medical_care_expenses.py
index bd9befac63b..166bd2ab754 100644
--- a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_uninsured_unreimbursed_medical_care_expenses.py
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_uninsured_unreimbursed_medical_care_expenses.py
@@ -8,22 +8,18 @@ class oh_uninsured_unreimbursed_medical_care_expenses(Variable):
     unit = USD
     definition_period = YEAR
     reference = (
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=18",  # Line 36
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=27",
-        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(10)
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)(a)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=25",  # Line 44, pp. 25-26
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet line 1
     )
     defined_for = StateCode.OH
 
     def formula(person, period, parameters):
-        not_medicare_eligible = ~person("is_medicare_eligible", period)
-        employer_premium_contribution = person(
-            "employer_contribution_to_health_insurance_premiums_category",
-            period,
+        premiums = person("oh_medical_care_insurance_premiums", period)
+        medicare_eligible = person("is_medicare_eligible", period)
+        employer_plan_eligible = person.tax_unit(
+            "oh_employer_subsidized_health_plan_eligible", period
         )
-        status = employer_premium_contribution.possible_values
-        health_insurance_premiums = person("health_insurance_premiums", period)
-        # Premiums only count if the employer paid none.
-        eligible_health_insurance_premiums = health_insurance_premiums * (
-            employer_premium_contribution == status.NONE
-        )
-        return not_medicare_eligible * eligible_health_insurance_premiums
+        # Line 1: premiums paid while eligible for neither Medicare nor an
+        # employer-paid plan. Otherwise they go on line 3.
+        return premiums * ~(medicare_eligible | employer_plan_eligible)
diff --git a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_unreimbursed_medical_care_expense_deduction.py b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_unreimbursed_medical_care_expense_deduction.py
index 2c9bbe3ffd9..ee0cc284978 100644
--- a/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_unreimbursed_medical_care_expense_deduction.py
+++ b/policyengine_us/variables/gov/states/oh/tax/income/deductions/medical_exepenses/oh_unreimbursed_medical_care_expense_deduction.py
@@ -8,9 +8,9 @@ class oh_unreimbursed_medical_care_expense_deduction(Variable):
     unit = USD
     definition_period = YEAR
     reference = (
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=18",  # Line 36
-        "https://tax.ohio.gov/static/forms/ohio_individual/individual/2022/it1040-sd100-instruction-booklet.pdf#page=27",
-        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(10)
+        "https://codes.ohio.gov/ohio-revised-code/section-5747.01",  # R.C. 5747.01(A)(10)
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=25",  # Line 44, pp. 25-26
+        "https://dam.assets.ohio.gov/image/upload/v1767095693/tax.ohio.gov/forms/ohio_individual/individual/2025/it1040-booklet.pdf#page=41",  # Worksheet
     )
     defined_for = StateCode.OH