diff --git a/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache b/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
index 7937e6fabe75..872dc9e8ee7c 100644
--- a/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
+++ b/modules/openapi-generator/src/main/resources/dart2/serialization/native/native_class.mustache
@@ -171,7 +171,12 @@ class {{{classname}}} {
                   {{/items.complexType}}
                 {{/items.isMap}}
                 {{^items.isMap}}
-        {{{name}}}: mapValueOfType<{{{datatypeWithEnum}}}>(json, r'{{{baseName}}}'){{#required}}{{^isNullable}}!{{/isNullable}}{{/required}}{{^required}}{{#defaultValue}} ?? {{{.}}}{{/defaultValue}}{{/required}},
+                  {{#items.complexType}}
+        {{{name}}}: {{{items.complexType}}}.mapFromJson(json[r'{{{baseName}}}'{{#required}}{{^isNullable}}!{{/isNullable}}{{/required}}{{^required}}{{#defaultValue}}]) ?? {{{.}}}{{/defaultValue}}{{/required}},
+                  {{/items.complexType}}
+                  {{^items.complexType}}
+        {{{name}}}: mapCastOfType<String, {{items.dataType}}>(json, r'{{{baseName}}}'){{#required}}{{^isNullable}}!{{/isNullable}}{{/required}}{{^required}}{{#defaultValue}} ?? {{{.}}}{{/defaultValue}}{{/required}},
+                  {{/items.complexType}}
                 {{/items.isMap}}
               {{/items.isArray}}
             {{/isMap}}
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
index ce90481b6cd3..b281b0a0598b 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart
@@ -85,7 +85,7 @@ class MixedPropertiesAndAdditionalPropertiesClass {
       return MixedPropertiesAndAdditionalPropertiesClass(
         uuid: mapValueOfType<String>(json, r'uuid'),
         dateTime: mapDateTime(json, r'dateTime', ''),
-        map: mapValueOfType<Map<String, Animal>>(json, r'map') ?? const {},
+        map: Animal.mapFromJson(json[r'map']) ?? const {},
       );
     }
     return null;
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
index 7dce3d71cf40..b8a0878b3056 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/model/nullable_class.dart
@@ -152,9 +152,9 @@ class NullableClass {
         arrayNullableProp: Object.listFromJson(json[r'array_nullable_prop']) ?? const [],
         arrayAndItemsNullableProp: Object.listFromJson(json[r'array_and_items_nullable_prop']) ?? const [],
         arrayItemsNullable: Object.listFromJson(json[r'array_items_nullable']) ?? const [],
-        objectNullableProp: mapValueOfType<Map<String, Object>>(json, r'object_nullable_prop') ?? const {},
-        objectAndItemsNullableProp: mapValueOfType<Map<String, Object>>(json, r'object_and_items_nullable_prop') ?? const {},
-        objectItemsNullable: mapValueOfType<Map<String, Object>>(json, r'object_items_nullable') ?? const {},
+        objectNullableProp: mapCastOfType<String, Object>(json, r'object_nullable_prop') ?? const {},
+        objectAndItemsNullableProp: mapCastOfType<String, Object>(json, r'object_and_items_nullable_prop') ?? const {},
+        objectItemsNullable: mapCastOfType<String, Object>(json, r'object_items_nullable') ?? const {},
       );
     }
     return null;