diff --git a/builtin/submodule--helper.c b/builtin/submodule--helper.c
index df22e97afa..2fc9658625 100644
--- a/builtin/submodule--helper.c
+++ b/builtin/submodule--helper.c
@@ -515,7 +515,7 @@ static int module_clone(int argc, const char **argv, const char *prefix)
 		usage_with_options(git_submodule_helper_usage,
 				   module_clone_options);
 
-	if (argc)
+	if (argc || !url)
 		usage_with_options(git_submodule_helper_usage,
 				   module_clone_options);