diff --git a/webrtc/p2p/base/relayserver_unittest.cc b/webrtc/p2p/base/relayserver_unittest.cc
index 0bff03999..8c1c0aed9 100644
--- a/webrtc/p2p/base/relayserver_unittest.cc
+++ b/webrtc/p2p/base/relayserver_unittest.cc
@@ -486,8 +486,14 @@ TEST_F(RelayServerTest, TestSendRaw) {
   }
 }
 
+// Flaky on Mac, see https://code.google.com/p/webrtc/issues/detail?id=4134
+#if defined(WEBRTC_MAC)
+#define MAYBE_TestExpiration DISABLED_TestExpiration
+#else
+#define MAYBE_TestExpiration TestExpiration
+#endif
 // Verify that a binding expires properly, and rejects send requests.
-TEST_F(RelayServerTest, TestExpiration) {
+TEST_F(RelayServerTest, MAYBE_TestExpiration) {
   Allocate();
   Bind();