diff --git a/libmpcodecs/vf_remove_logo.c b/libmpcodecs/vf_remove_logo.c
index b917326950..9c1c8d6206 100644
--- a/libmpcodecs/vf_remove_logo.c
+++ b/libmpcodecs/vf_remove_logo.c
@@ -87,6 +87,7 @@ __________________________________________________________________________
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <ctype.h>
 #include <inttypes.h>
 
 #include "../config.h"