diff --git a/modules/openapi-generator/src/main/resources/dart-dio/api.mustache b/modules/openapi-generator/src/main/resources/dart-dio/api.mustache
index 112fd77f9993..48b73d914c02 100644
--- a/modules/openapi-generator/src/main/resources/dart-dio/api.mustache
+++ b/modules/openapi-generator/src/main/resources/dart-dio/api.mustache
@@ -55,6 +55,9 @@ class {{classname}} {
                 }
             {{/isFile}}
         {{/isMultipart}}
+        {{^isMultipart}}
+            formData['{{baseName}}'] = parameterToString(_serializers, {{paramName}});
+        {{/isMultipart}}
         {{/formParams}}
         bodyData = FormData.fromMap(formData);
         {{/hasFormParams}}
diff --git a/samples/client/petstore/dart-dio/.openapi-generator/VERSION b/samples/client/petstore/dart-dio/.openapi-generator/VERSION
index b5d898602c2c..9e9d3e448fb4 100644
--- a/samples/client/petstore/dart-dio/.openapi-generator/VERSION
+++ b/samples/client/petstore/dart-dio/.openapi-generator/VERSION
@@ -1 +1 @@
-4.3.1-SNAPSHOT
\ No newline at end of file
+4.3.1-SNAPSHOT
diff --git a/samples/client/petstore/dart-dio/lib/api/pet_api.dart b/samples/client/petstore/dart-dio/lib/api/pet_api.dart
index 5c78e6e6204c..c5a66f32cc7a 100644
--- a/samples/client/petstore/dart-dio/lib/api/pet_api.dart
+++ b/samples/client/petstore/dart-dio/lib/api/pet_api.dart
@@ -266,6 +266,8 @@ class PetApi {
         List<String> contentTypes = ["application/x-www-form-urlencoded"];
 
         Map<String, dynamic> formData = {};
+            formData['name'] = parameterToString(_serializers, name);
+            formData['status'] = parameterToString(_serializers, status);
         bodyData = FormData.fromMap(formData);