diff --git a/res/res_agi.c b/res/res_agi.c
index e868601bd2e93efcdc96e1c13ada754351dab191..0a468f443f8a799660f3792bd2aaba5bf4f91742 100644
--- a/res/res_agi.c
+++ b/res/res_agi.c
@@ -2553,6 +2553,9 @@ static int handle_noop(struct ast_channel *chan, AGI *agi, int arg, const char *
 
 static int handle_setmusic(struct ast_channel *chan, AGI *agi, int argc, const char * const argv[])
 {
+	if (argc < 3) {
+		return RESULT_SHOWUSAGE;
+	}
 	if (!strncasecmp(argv[2], "on", 2))
 		ast_moh_start(chan, argc > 3 ? argv[3] : NULL, NULL);
 	else if (!strncasecmp(argv[2], "off", 3))