diff --git a/include/rfl/json/schema/Type.hpp b/include/rfl/json/schema/Type.hpp
index 0fc46d8d..2efddc2f 100644
--- a/include/rfl/json/schema/Type.hpp
+++ b/include/rfl/json/schema/Type.hpp
@@ -101,7 +101,7 @@ struct Type {
     rfl::Flatten<Annotations> annotations{};
     rfl::Object<Type> properties{};
     std::vector<std::string> required{};
-    std::shared_ptr<Type> additionalProperties{};
+    rfl::Variant<bool, std::shared_ptr<Type>> additionalProperties{};
   };
 
   struct OneOf {
diff --git a/include/rfl/parsing/NamedTupleParser.hpp b/include/rfl/parsing/NamedTupleParser.hpp
index 8542cdb7..859958a0 100644
--- a/include/rfl/parsing/NamedTupleParser.hpp
+++ b/include/rfl/parsing/NamedTupleParser.hpp
@@ -15,6 +15,7 @@
 #include "../internal/is_default_val_v.hpp"
 #include "../internal/is_extra_fields.hpp"
 #include "../internal/is_skip.hpp"
+#include "../internal/no_extra_fields_v.hpp"
 #include "../internal/nth_element_t.hpp"
 #include "../internal/ptr_cast.hpp"
 #include "../to_view.hpp"
@@ -284,6 +285,9 @@ struct NamedTupleParser {
       using U = std::remove_cvref_t<typename ExtraFieldsType::Type>;
       _schema->additional_properties_ = std::make_shared<schema::Type>(
           Parser<R, W, U, ProcessorsType>::to_schema(_definitions));
+    } else if constexpr (internal::no_extra_fields_v<ProcessorsType> &&
+                         !_no_field_names) {
+      _schema->additional_properties_ = false;
     }
   }
 
diff --git a/include/rfl/parsing/schema/Type.hpp b/include/rfl/parsing/schema/Type.hpp
index a3621b2a..f4d0ad82 100644
--- a/include/rfl/parsing/schema/Type.hpp
+++ b/include/rfl/parsing/schema/Type.hpp
@@ -79,7 +79,7 @@ struct RFL_API Type {
 
   struct Object {
     rfl::Object<Type> types_;
-    std::shared_ptr<Type> additional_properties_;
+    rfl::Variant<bool, std::shared_ptr<Type>> additional_properties_;
   };
 
   /// All values are assumed to be required unless explicitly stated otherwise
diff --git a/src/rfl/json/to_schema.cpp b/src/rfl/json/to_schema.cpp
index b6ed76cd..4496398c 100644
--- a/src/rfl/json/to_schema.cpp
+++ b/src/rfl/json/to_schema.cpp
@@ -285,11 +285,19 @@ schema::Type type_to_json_schema_type(const parsing::schema::Type& _type,
           required.push_back(k);
         }
       }
-      auto additional_properties =
-          _t.additional_properties_
-              ? std::make_shared<schema::Type>(type_to_json_schema_type(
-                    *_t.additional_properties_, _no_required))
-              : std::shared_ptr<schema::Type>();
+      auto additional_properties = rfl::visit(
+          [&](const auto& _a)
+              -> rfl::Variant<bool, std::shared_ptr<schema::Type>> {
+            using A = std::remove_cvref_t<decltype(_a)>;
+            if constexpr (std::is_same<A, bool>()) {
+              return _a;
+            } else {
+              return _a ? std::make_shared<schema::Type>(
+                              type_to_json_schema_type(*_a, _no_required))
+                        : std::shared_ptr<schema::Type>();
+            }
+          },
+          _t.additional_properties_);
       return schema::Type{.value = schema::Type::Object{
                               .properties = properties,
                               .required = required,