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 024883ad99af..38f4deb96f84 100644
--- a/modules/openapi-generator/src/main/resources/dart-dio/api.mustache
+++ b/modules/openapi-generator/src/main/resources/dart-dio/api.mustache
@@ -108,7 +108,7 @@ class {{classname}} {
     {{#returnType}}
 
     {{#isResponseFile}}
-    final {{{returnType}}} _responseData = _response.data;
+    final {{{returnType}}} _responseData = _response.data as {{{returnType}}};
     {{/isResponseFile}}
     {{^isResponseFile}}
     {{#returnSimpleType}}