diff --git a/modules/openapi-generator/src/main/resources/dart2/api_helper.mustache b/modules/openapi-generator/src/main/resources/dart2/api_helper.mustache
index 6268a5af3e48..7b662906bdee 100644
--- a/modules/openapi-generator/src/main/resources/dart2/api_helper.mustache
+++ b/modules/openapi-generator/src/main/resources/dart2/api_helper.mustache
@@ -69,6 +69,9 @@ Future<String> _decodeBodyBytes(Response response) async {
 /// Returns a valid [T] value found at the specified Map [key], null otherwise.
 T? mapValueOfType<T>(dynamic map, String key) {
   final dynamic value = map is Map ? map[key] : null;
+  if (T == double && value is int) {
+    return value.toDouble() as T;
+  }
   return value is T ? value : null;
 }
 
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api_helper.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api_helper.dart
index bf83e9172195..255f38d9bc94 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api_helper.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib/lib/api_helper.dart
@@ -70,6 +70,9 @@ Future<String> _decodeBodyBytes(Response response) async {
 /// Returns a valid [T] value found at the specified Map [key], null otherwise.
 T? mapValueOfType<T>(dynamic map, String key) {
   final dynamic value = map is Map ? map[key] : null;
+  if (T == double && value is int) {
+    return value.toDouble() as T;
+  }
   return value is T ? value : null;
 }
 
diff --git a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_helper.dart b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_helper.dart
index 1a1fe1b2d562..a07a5497a661 100644
--- a/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_helper.dart
+++ b/samples/openapi3/client/petstore/dart2/petstore_client_lib_fake/lib/api_helper.dart
@@ -88,6 +88,9 @@ Future<String> _decodeBodyBytes(Response response) async {
 /// Returns a valid [T] value found at the specified Map [key], null otherwise.
 T? mapValueOfType<T>(dynamic map, String key) {
   final dynamic value = map is Map ? map[key] : null;
+  if (T == double && value is int) {
+    return value.toDouble() as T;
+  }
   return value is T ? value : null;
 }