diff --git a/modules/openapi-generator/src/main/resources/typescript-axios/apiInner.mustache b/modules/openapi-generator/src/main/resources/typescript-axios/apiInner.mustache
index 3f625aca23de..dc839d57cf7b 100644
--- a/modules/openapi-generator/src/main/resources/typescript-axios/apiInner.mustache
+++ b/modules/openapi-generator/src/main/resources/typescript-axios/apiInner.mustache
@@ -115,7 +115,9 @@ export const {{classname}}AxiosParamCreator = function (configuration?: Configur
             {{^isListContainer}}
             if ({{paramName}} !== undefined) {
                 {{#isDateTime}}
-                localVarQueryParameter['{{baseName}}'] = ({{paramName}} as any).toISOString();
+                localVarQueryParameter['{{baseName}}'] = ({{paramName}} as any instanceof Date) ?
+                    ({{paramName}} as any).toISOString() :
+                    {{paramName}};
                 {{/isDateTime}}
                 {{^isDateTime}}
                 {{#isDate}}