diff --git a/libretro-common/streams/file_stream.c b/libretro-common/streams/file_stream.c
index b5d54b6223..2718fbc49e 100644
--- a/libretro-common/streams/file_stream.c
+++ b/libretro-common/streams/file_stream.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
+#include <ctype.h>
 #include <errno.h>
 
 #ifdef HAVE_CONFIG_H