diff --git a/media/engine/simulcast.cc b/media/engine/simulcast.cc
index 6a01016f99..0103051bcc 100644
--- a/media/engine/simulcast.cc
+++ b/media/engine/simulcast.cc
@@ -397,7 +397,7 @@ std::vector<webrtc::VideoStream> GetScreenshareLayers(
 }
 
 bool ScreenshareSimulcastFieldTrialEnabled() {
-  return webrtc::field_trial::IsEnabled(kSimulcastScreenshareFieldTrialName);
+  return !webrtc::field_trial::IsDisabled(kSimulcastScreenshareFieldTrialName);
 }
 
 }  // namespace cricket
diff --git a/media/engine/simulcast_unittest.cc b/media/engine/simulcast_unittest.cc
index 0c27816068..ecc697ce26 100644
--- a/media/engine/simulcast_unittest.cc
+++ b/media/engine/simulcast_unittest.cc
@@ -222,6 +222,7 @@ TEST(SimulcastTest, GetConfigWithNormalizedResolutionDivisibleBy8) {
 }
 
 TEST(SimulcastTest, GetConfigForScreenshare) {
+  test::ScopedFieldTrials field_trials("WebRTC-SimulcastScreenshare/Disabled/");
   const size_t kMaxLayers = 3;
   std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
       kMaxLayers, 1400, 800, kMaxBitrateBps, kBitratePriority, kQpMax, kMaxFps,
@@ -241,8 +242,6 @@ TEST(SimulcastTest, GetConfigForScreenshare) {
 }
 
 TEST(SimulcastTest, GetConfigForScreenshareSimulcast) {
-  test::ScopedFieldTrials field_trials("WebRTC-SimulcastScreenshare/Enabled/");
-
   const size_t kMaxLayers = 3;
   std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
       kMaxLayers, 1400, 800, kMaxBitrateBps, kBitratePriority, kQpMax, kMaxFps,
@@ -263,8 +262,6 @@ TEST(SimulcastTest, GetConfigForScreenshareSimulcast) {
 }
 
 TEST(SimulcastTest, GetConfigForScreenshareSimulcastWithLimitedMaxLayers) {
-  test::ScopedFieldTrials field_trials("WebRTC-SimulcastScreenshare/Enabled/");
-
   const size_t kMaxLayers = 1;
   std::vector<VideoStream> streams = cricket::GetSimulcastConfig(
       kMaxLayers, 1400, 800, kMaxBitrateBps, kBitratePriority, kQpMax, kMaxFps,
@@ -274,8 +271,6 @@ TEST(SimulcastTest, GetConfigForScreenshareSimulcastWithLimitedMaxLayers) {
 }
 
 TEST(SimulcastTest, SimulcastScreenshareMaxBitrateAdjustedForResolution) {
-  test::ScopedFieldTrials field_trials("WebRTC-SimulcastScreenshare/Enabled/");
-
   constexpr int kScreenshareHighStreamMinBitrateBps = 600000;
   constexpr int kScreenshareHighStreamMaxBitrateBps = 1250000;
   constexpr int kMaxBitrate960_540 = 900000;
diff --git a/media/engine/webrtcvideoengine_unittest.cc b/media/engine/webrtcvideoengine_unittest.cc
index ab04fa6af3..543fa3a71b 100644
--- a/media/engine/webrtcvideoengine_unittest.cc
+++ b/media/engine/webrtcvideoengine_unittest.cc
@@ -6976,21 +6976,19 @@ TEST_F(WebRtcVideoChannelSimulcastTest, SetSendCodecsForScreenshare) {
 
 TEST_F(WebRtcVideoChannelSimulcastTest,
        SetSendCodecsForConferenceModeScreenshare) {
+  webrtc::test::ScopedFieldTrials field_trials(
+      "WebRTC-SimulcastScreenshare/Disabled/");
   VerifySimulcastSettings(cricket::VideoCodec("VP8"), 1280, 720, 3, 1, true,
                           true);
 }
 
 TEST_F(WebRtcVideoChannelSimulcastTest, SetSendCodecsForSimulcastScreenshare) {
-  webrtc::test::ScopedFieldTrials override_field_trials_(
-      "WebRTC-SimulcastScreenshare/Enabled/");
   VerifySimulcastSettings(cricket::VideoCodec("VP8"), 1280, 720, 3, 2, true,
                           true);
 }
 
 TEST_F(WebRtcVideoChannelSimulcastTest,
        NoSimulcastScreenshareWithoutConference) {
-  webrtc::test::ScopedFieldTrials override_field_trials_(
-      "WebRTC-SimulcastScreenshare/Enabled/");
   VerifySimulcastSettings(cricket::VideoCodec("VP8"), 1280, 720, 3, 1, true,
                           false);
 }