--- a/security/manager/ssl/nsNSSCertificate.h
+++ b/security/manager/ssl/nsNSSCertificate.h
@@ -1,16 +1,18 @@
 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 #ifndef nsNSSCertificate_h
 #define nsNSSCertificate_h
 
+#include <functional>
+
 #include "ScopedNSSTypes.h"
 #include "certt.h"
 #include "nsCOMPtr.h"
 #include "nsIASN1Object.h"
 #include "nsIClassInfo.h"
 #include "nsISerializable.h"
 #include "nsISimpleEnumerator.h"
 #include "nsIX509Cert.h"