diff --git a/lib/nss.c b/lib/nss.c
index 02fa06d9c..15942a3e6 100644
--- a/lib/nss.c
+++ b/lib/nss.c
@@ -63,6 +63,7 @@
 #include <secitem.h>
 #include <secport.h>
 #include <certdb.h>
+#include <base64.h>
 
 #include "curl_memory.h"
 #include "rawstr.h"