diff --git a/webrtc/base/physicalsocketserver_unittest.cc b/webrtc/base/physicalsocketserver_unittest.cc
index 6de8a90ea8..37d412dc1f 100644
--- a/webrtc/base/physicalsocketserver_unittest.cc
+++ b/webrtc/base/physicalsocketserver_unittest.cc
@@ -404,18 +404,14 @@ TEST_F(PhysicalSocketTest, TestGetSetOptionsIPv6) {
 
 #if defined(WEBRTC_POSIX)
 
+// We don't get recv timestamps on Mac.
 #if !defined(WEBRTC_MAC)
 TEST_F(PhysicalSocketTest, TestSocketRecvTimestampIPv4) {
-  SocketTest::TestSocketRecvTimestamp();
+  SocketTest::TestSocketRecvTimestampIPv4();
 }
 
-#if defined(WEBRTC_LINUX)
-#define MAYBE_TestSocketRecvTimestampIPv6 DISABLED_TestSocketRecvTimestampIPv6
-#else
-#define MAYBE_TestSocketRecvTimestampIPv6 TestSocketRecvTimestampIPv6
-#endif
-TEST_F(PhysicalSocketTest, MAYBE_TestSocketRecvTimestampIPv6) {
-  SocketTest::TestSocketRecvTimestamp();
+TEST_F(PhysicalSocketTest, TestSocketRecvTimestampIPv6) {
+  SocketTest::TestSocketRecvTimestampIPv6();
 }
 #endif
 
diff --git a/webrtc/base/socket.h b/webrtc/base/socket.h
index 7db9459de7..73dfdbb808 100644
--- a/webrtc/base/socket.h
+++ b/webrtc/base/socket.h
@@ -151,6 +151,7 @@ class Socket {
   virtual int Connect(const SocketAddress& addr) = 0;
   virtual int Send(const void *pv, size_t cb) = 0;
   virtual int SendTo(const void *pv, size_t cb, const SocketAddress& addr) = 0;
+  // |timestamp| is in units of microseconds.
   virtual int Recv(void* pv, size_t cb, int64_t* timestamp) = 0;
   virtual int RecvFrom(void* pv,
                        size_t cb,
diff --git a/webrtc/base/socket_unittest.cc b/webrtc/base/socket_unittest.cc
index c206220a97..5dc52511e4 100644
--- a/webrtc/base/socket_unittest.cc
+++ b/webrtc/base/socket_unittest.cc
@@ -184,10 +184,15 @@ void SocketTest::TestGetSetOptionsIPv6() {
   GetSetOptionsInternal(kIPv6Loopback);
 }
 
-void SocketTest::TestSocketRecvTimestamp() {
+void SocketTest::TestSocketRecvTimestampIPv4() {
   SocketRecvTimestamp(kIPv4Loopback);
 }
 
+void SocketTest::TestSocketRecvTimestampIPv6() {
+  MAYBE_SKIP_IPV6;
+  SocketRecvTimestamp(kIPv6Loopback);
+}
+
 // For unbound sockets, GetLocalAddress / GetRemoteAddress return AF_UNSPEC
 // values on Windows, but an empty address of the same family on Linux/MacOS X.
 bool IsUnspecOrEmptyIP(const IPAddress& address) {
@@ -1033,19 +1038,26 @@ void SocketTest::SocketRecvTimestamp(const IPAddress& loopback) {
   EXPECT_EQ(0, socket->Bind(SocketAddress(loopback, 0)));
   SocketAddress address = socket->GetLocalAddress();
 
+  uint64_t send_time_1 = TimeMicros();
   socket->SendTo("foo", 3, address);
-  int64_t timestamp;
+  int64_t recv_timestamp_1;
   char buffer[3];
-  socket->RecvFrom(buffer, 3, nullptr, &timestamp);
-  EXPECT_GT(timestamp, -1);
-  int64_t prev_timestamp = timestamp;
+  socket->RecvFrom(buffer, 3, nullptr, &recv_timestamp_1);
+  EXPECT_GT(recv_timestamp_1, -1);
 
-  const int64_t kTimeBetweenPacketsMs = 10;
+  const int64_t kTimeBetweenPacketsMs = 100;
   Thread::SleepMs(kTimeBetweenPacketsMs);
 
+  uint64_t send_time_2 = TimeMicros();
   socket->SendTo("bar", 3, address);
-  socket->RecvFrom(buffer, 3, nullptr, &timestamp);
-  EXPECT_NEAR(timestamp, prev_timestamp + kTimeBetweenPacketsMs * 1000, 2000);
+  int64_t recv_timestamp_2;
+  socket->RecvFrom(buffer, 3, nullptr, &recv_timestamp_2);
+
+  int64_t system_time_diff = send_time_2 - send_time_1;
+  int64_t recv_timestamp_diff = recv_timestamp_2 - recv_timestamp_1;
+  // Compare against the system time at the point of sending, because
+  // SleepMs may not sleep for exactly the requested time.
+  EXPECT_NEAR(system_time_diff, recv_timestamp_diff, 10000);
 }
 
 }  // namespace rtc
diff --git a/webrtc/base/socket_unittest.h b/webrtc/base/socket_unittest.h
index 82b7ea5aaf..8172edd036 100644
--- a/webrtc/base/socket_unittest.h
+++ b/webrtc/base/socket_unittest.h
@@ -57,7 +57,8 @@ class SocketTest : public testing::Test {
   void TestUdpReadyToSendIPv6();
   void TestGetSetOptionsIPv4();
   void TestGetSetOptionsIPv6();
-  void TestSocketRecvTimestamp();
+  void TestSocketRecvTimestampIPv4();
+  void TestSocketRecvTimestampIPv6();
 
   static const int kTimeout = 5000;  // ms
   const IPAddress kIPv4Loopback;