diff --git a/modules/audio_device/win/core_audio_utility_win.cc b/modules/audio_device/win/core_audio_utility_win.cc
index 4a02c4e14a..bcafccb301 100644
--- a/modules/audio_device/win/core_audio_utility_win.cc
+++ b/modules/audio_device/win/core_audio_utility_win.cc
@@ -28,6 +28,7 @@ using Microsoft::WRL::ComPtr;
 using webrtc::AudioDeviceName;
 using webrtc::AudioParameters;
 
+namespace webrtc {
 namespace webrtc_win {
 namespace {
 
@@ -824,3 +825,4 @@ std::string ErrorToString(const _com_error& error) {
 
 }  // namespace core_audio_utility
 }  // namespace webrtc_win
+}  // namespace webrtc
diff --git a/modules/audio_device/win/core_audio_utility_win.h b/modules/audio_device/win/core_audio_utility_win.h
index 2b49592eba..c78743191b 100644
--- a/modules/audio_device/win/core_audio_utility_win.h
+++ b/modules/audio_device/win/core_audio_utility_win.h
@@ -26,6 +26,7 @@
 #include "modules/audio_device/include/audio_device_defines.h"
 #include "rtc_base/logging.h"
 
+namespace webrtc {
 namespace webrtc_win {
 
 static const int64_t kNumMicrosecsPerSec = webrtc::TimeDelta::seconds(1).us();
@@ -427,5 +428,6 @@ std::string ErrorToString(const _com_error& error);
 
 }  // namespace core_audio_utility
 }  // namespace webrtc_win
+}  // namespace webrtc
 
 #endif  //  MODULES_AUDIO_DEVICE_WIN_CORE_AUDIO_UTILITY_WIN_H_
diff --git a/modules/audio_device/win/core_audio_utility_win_unittest.cc b/modules/audio_device/win/core_audio_utility_win_unittest.cc
index b03a259346..35241762eb 100644
--- a/modules/audio_device/win/core_audio_utility_win_unittest.cc
+++ b/modules/audio_device/win/core_audio_utility_win_unittest.cc
@@ -16,6 +16,7 @@
 using Microsoft::WRL::ComPtr;
 using webrtc::AudioDeviceName;
 
+namespace webrtc {
 namespace webrtc_win {
 namespace {
 
@@ -561,3 +562,4 @@ TEST_F(CoreAudioUtilityWinTest, FillRenderEndpointBufferWithSilence) {
 }
 
 }  // namespace webrtc_win
+}  // namespace webrtc