diff --git a/app.go b/app.go
index 485c92b..44d6645 100644
--- a/app.go
+++ b/app.go
@@ -342,6 +342,7 @@ func (a *App) RunAsSubcommand(ctx *Context) (err error) {
 
 	cerr := checkRequiredFlags(a.Flags, set)
 	if cerr != nil {
+		showFlagError(a.Writer, cerr)
 		ShowSubcommandHelp(context)
 		return cerr
 	}