diff --git a/changes/private-in-printed-types.fix.md b/changes/private-in-printed-types.fix.md
new file mode 100644
index 0000000000..a843b18f2f
--- /dev/null
+++ b/changes/private-in-printed-types.fix.md
@@ -0,0 +1 @@
+- Print `private` for abbreviations and variants in type mismatch errors and other printed type declarations.
diff --git a/compiler/syntax/src/res_outcome_printer.ml b/compiler/syntax/src/res_outcome_printer.ml
index 7ad5747e51..54a560a445 100644
--- a/compiler/syntax/src/res_outcome_printer.ml
+++ b/compiler/syntax/src/res_outcome_printer.ml
@@ -694,7 +694,16 @@ let rec print_out_sig_item_doc ?(print_name_as_is = false)
             private_doc;
             print_record_declaration_doc ~inline:false record;
           ]
-      | typ -> Doc.concat [Doc.text " = "; print_out_type_doc typ]
+      | Otyp_manifest (manifest, typ) ->
+        Doc.concat
+          [
+            Doc.text " = ";
+            print_out_type_doc manifest;
+            Doc.text " = ";
+            private_doc;
+            print_out_type_doc typ;
+          ]
+      | typ -> Doc.concat [Doc.text " = "; private_doc; print_out_type_doc typ]
     in
     let constraints =
       match out_type_decl.otype_cstrs with
diff --git a/tests/build_tests/super_errors/expected/object_private_row_grants_set.res.expected b/tests/build_tests/super_errors/expected/object_private_row_grants_set.res.expected
index 1d1d476ef9..7b18c2610c 100644
--- a/tests/build_tests/super_errors/expected/object_private_row_grants_set.res.expected
+++ b/tests/build_tests/super_errors/expected/object_private_row_grants_set.res.expected
@@ -12,16 +12,16 @@
   Signature mismatch:
   Modules do not match:
     {
-  type t = {.."x": int}
+  type t = private {.."x": int}
 }
   is not included in
     {
-  type t = {..@set "x": int}
+  type t = private {..@set "x": int}
 }
   Type declarations do not match:
-    type t = {.."x": int}
+    type t = private {.."x": int}
   is not included in
-    type t = {..@set "x": int}
+    type t = private {..@set "x": int}
   /.../fixtures/object_private_row_grants_set.res:6:3-36:
     Expected declaration
   /.../fixtures/object_private_row_grants_set.res:8:3-31:
diff --git a/tests/build_tests/super_errors_multi/expected/Cross_private_abbreviation_mismatch.expected b/tests/build_tests/super_errors_multi/expected/Cross_private_abbreviation_mismatch.expected
new file mode 100644
index 0000000000..71730354d1
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/expected/Cross_private_abbreviation_mismatch.expected
@@ -0,0 +1,20 @@
+===== Priv.res =====
+
+  We've found a bug for you!
+  /.../fixtures/Cross_private_abbreviation_mismatch/Priv.res:3:1-10
+
+  1 │ type a
+  2 │ type b
+  3 │ type t = b
+  4 │ 
+
+  The implementation /.../fixtures/Cross_private_abbreviation_mismatch/Priv.res
+  does not match the interface /.../fixtures/Cross_private_abbreviation_mismatch/priv.cmi:
+  Type declarations do not match:
+    type t = b
+  is not included in
+    type t = private a
+  /.../fixtures/Cross_private_abbreviation_mismatch/Priv.resi:2:1-18:
+    Expected declaration
+  /.../fixtures/Cross_private_abbreviation_mismatch/Priv.res:3:1-10:
+    Actual declaration
\ No newline at end of file
diff --git a/tests/build_tests/super_errors_multi/expected/Cross_private_variant_manifest_mismatch.expected b/tests/build_tests/super_errors_multi/expected/Cross_private_variant_manifest_mismatch.expected
new file mode 100644
index 0000000000..2e76d32d92
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/expected/Cross_private_variant_manifest_mismatch.expected
@@ -0,0 +1,19 @@
+===== Priv.res =====
+
+  We've found a bug for you!
+  /.../fixtures/Cross_private_variant_manifest_mismatch/Priv.res:2:1-14
+
+  1 │ type v = A | B
+  2 │ type w = A | B
+  3 │ 
+
+  The implementation /.../fixtures/Cross_private_variant_manifest_mismatch/Priv.res
+  does not match the interface /.../fixtures/Cross_private_variant_manifest_mismatch/priv.cmi:
+  Type declarations do not match:
+    type w = A | B
+  is not included in
+    type w = v = private A | B
+  /.../fixtures/Cross_private_variant_manifest_mismatch/Priv.resi:2:1-26:
+    Expected declaration
+  /.../fixtures/Cross_private_variant_manifest_mismatch/Priv.res:2:1-14:
+    Actual declaration
\ No newline at end of file
diff --git a/tests/build_tests/super_errors_multi/expected/Iface_privacy_mismatch.expected b/tests/build_tests/super_errors_multi/expected/Iface_privacy_mismatch.expected
index 621a81f6ec..c8b4726a2b 100644
--- a/tests/build_tests/super_errors_multi/expected/Iface_privacy_mismatch.expected
+++ b/tests/build_tests/super_errors_multi/expected/Iface_privacy_mismatch.expected
@@ -9,7 +9,7 @@
   The implementation /.../fixtures/Iface_privacy_mismatch/Foo.res
   does not match the interface /.../fixtures/Iface_privacy_mismatch/foo.cmi:
   Type declarations do not match:
-    type t = int
+    type t = private int
   is not included in
     type t = int
   /.../fixtures/Iface_privacy_mismatch/Foo.resi:1:1-12:
diff --git a/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.res b/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.res
new file mode 100644
index 0000000000..bae91f6e9f
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.res
@@ -0,0 +1,3 @@
+type a
+type b
+type t = b
diff --git a/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.resi b/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.resi
new file mode 100644
index 0000000000..01325fdbda
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/fixtures/Cross_private_abbreviation_mismatch/Priv.resi
@@ -0,0 +1,2 @@
+type a
+type t = private a
diff --git a/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.res b/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.res
new file mode 100644
index 0000000000..c148fc66c1
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.res
@@ -0,0 +1,2 @@
+type v = A | B
+type w = A | B
diff --git a/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.resi b/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.resi
new file mode 100644
index 0000000000..4e9712b903
--- /dev/null
+++ b/tests/build_tests/super_errors_multi/fixtures/Cross_private_variant_manifest_mismatch/Priv.resi
@@ -0,0 +1,2 @@
+type v = A | B
+type w = v = private A | B