diff --git a/admin/ktutil_locl.h b/admin/ktutil_locl.h
index b34db6cd6..6dc852c14 100644
--- a/admin/ktutil_locl.h
+++ b/admin/ktutil_locl.h
@@ -61,6 +61,7 @@
 
 #include <sl.h>
 #include <getarg.h>
+#include <hex.h>
 
 extern krb5_context context;