diff --git a/modules/swagger-codegen/src/main/resources/php/api.mustache b/modules/swagger-codegen/src/main/resources/php/api.mustache
index e0b01e1f678..442a76fe010 100644
--- a/modules/swagger-codegen/src/main/resources/php/api.mustache
+++ b/modules/swagger-codegen/src/main/resources/php/api.mustache
@@ -403,6 +403,7 @@ use {{invokerPackage}}\ObjectSerializer;
             {{/isFile}}
         }
         {{/formParams}}
+        $multipart = !empty($formParams);
         // body params
         $_tempBody = null;
         {{#bodyParams}}