diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 7bd68f277b..5d4b84482b 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1624,6 +1624,7 @@ void create_user_command(String name, Object command, Dict(user_command) *opts,
 err:
   NLUA_CLEAR_REF(luaref);
   NLUA_CLEAR_REF(compl_luaref);
+  xfree(compl_arg);
 }
 
 int find_sid(uint64_t channel_id)