diff --git a/lib/non-ascii.c b/lib/non-ascii.c
index d0e98266b..14143248f 100644
--- a/lib/non-ascii.c
+++ b/lib/non-ascii.c
@@ -30,6 +30,7 @@
 #include "formdata.h"
 #include "sendf.h"
 #include "urldata.h"
+#include "multiif.h"
 
 #include "curl_memory.h"
 /* The last #include file should be: */