diff --git a/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h b/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h
index ddac3cd113..f82e46d572 100644
--- a/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h
+++ b/webrtc/modules/rtp_rtcp/source/forward_error_correction_internal.h
@@ -8,6 +8,9 @@
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
+#ifndef WEBRTC_MODULES_RTP_RTCP_SOURCE_FORWARD_ERROR_CORRECTION_INTERNAL_H_
+#define WEBRTC_MODULES_RTP_RTCP_SOURCE_FORWARD_ERROR_CORRECTION_INTERNAL_H_
+
 #include "webrtc/modules/rtp_rtcp/source/forward_error_correction.h"
 #include "webrtc/typedefs.h"
 
@@ -64,3 +67,4 @@ void GeneratePacketMasks(int num_media_packets, int num_fec_packets,
 
 }  // namespace internal
 }  // namespace webrtc
+#endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_FORWARD_ERROR_CORRECTION_INTERNAL_H_