diff --git a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/CallParticipantsState.kt b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/CallParticipantsState.kt
index 9132a22542..046ee44f4d 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/CallParticipantsState.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/CallParticipantsState.kt
@@ -197,6 +197,7 @@ data class CallParticipantsState(
 
   companion object {
     const val SMALL_GROUP_MAX = 6
+    const val PRE_JOIN_MUTE_THRESHOLD = 8
 
     @JvmField
     val MAX_OUTGOING_GROUP_RING_DURATION = TimeUnit.MINUTES.toMillis(1)
diff --git a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/CallEvent.kt b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/CallEvent.kt
index 7396775ddb..c60a04883e 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/CallEvent.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/CallEvent.kt
@@ -23,6 +23,7 @@ sealed interface CallEvent {
   data class ShowGroupCallSafetyNumberChange(val identityRecords: List<IdentityRecord>) : CallEvent
   data object SwitchToSpeaker : CallEvent
   data object ShowSwipeToSpeakerHint : CallEvent
+  data object ShowLargeGroupAutoMuteToast : CallEvent
   data class ShowRemoteMuteToast(private val muted: Recipient, private val mutedBy: Recipient) : CallEvent {
     fun getDescription(context: Context): String {
       return if (muted.isSelf && mutedBy.isSelf) {
diff --git a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallActivity.kt b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallActivity.kt
index 1453918c97..518df0bc3c 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallActivity.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallActivity.kt
@@ -960,6 +960,10 @@ class WebRtcCallActivity : BaseActivity(), SafetyNumberChangeDialog.Callback, Re
       is CallEvent.SwitchToSpeaker -> callScreen.switchToSpeakerView()
       is CallEvent.ShowSwipeToSpeakerHint -> callScreen.showSpeakerViewHint()
       is CallEvent.ShowRemoteMuteToast -> callScreen.showRemoteMuteToast(event.getDescription(this))
+      is CallEvent.ShowLargeGroupAutoMuteToast -> {
+        callScreen.onCallStateUpdate(CallControlsChange.MIC_OFF)
+        callScreen.showRemoteMuteToast(getString(R.string.WebRtcCallView__youve_been_muted_large_group))
+      }
       is CallEvent.ShowVideoTooltip -> {
         if (isInPipMode()) return
 
diff --git a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallViewModel.kt b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallViewModel.kt
index 93aa11b40c..b1346f06d9 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallViewModel.kt
+++ b/app/src/main/java/org/thoughtcrime/securesms/components/webrtc/v2/WebRtcCallViewModel.kt
@@ -101,6 +101,7 @@ class WebRtcCallViewModel : ViewModel() {
   private var previousParticipantList = Collections.emptyList<CallParticipant>()
   private var switchOnFirstScreenShare = true
   private var showScreenShareTip = true
+  private var hasShownAutoMuteToast = false
 
   var isCallStarting = false
     private set
@@ -313,6 +314,7 @@ class WebRtcCallViewModel : ViewModel() {
       }
     }
 
+    val wasMicrophoneEnabled = internalMicrophoneEnabled.value
     internalMicrophoneEnabled.value = localParticipant.isMicrophoneEnabled
     isAudioDeviceChangePending.value = webRtcViewModel.isAudioDeviceChangePending
 
@@ -320,6 +322,16 @@ class WebRtcCallViewModel : ViewModel() {
       remoteMutedBy.update { null }
     }
 
+    if (!hasShownAutoMuteToast &&
+      wasMicrophoneEnabled &&
+      !localParticipant.isMicrophoneEnabled &&
+      webRtcViewModel.state == WebRtcViewModel.State.CALL_PRE_JOIN &&
+      webRtcViewModel.remoteDevicesCount.orElse(0L) >= CallParticipantsState.PRE_JOIN_MUTE_THRESHOLD
+    ) {
+      hasShownAutoMuteToast = true
+      emitEvent(CallEvent.ShowLargeGroupAutoMuteToast)
+    }
+
     val state: CallParticipantsState = participantsState.value!!
     val wasScreenSharing: Boolean = state.focusedParticipant.isScreenSharing
     val newState: CallParticipantsState = CallParticipantsState.update(state, webRtcViewModel, enableVideo)
diff --git a/app/src/main/java/org/thoughtcrime/securesms/service/webrtc/GroupPreJoinActionProcessor.java b/app/src/main/java/org/thoughtcrime/securesms/service/webrtc/GroupPreJoinActionProcessor.java
index 1e6a9cce3e..ba8e4e94e3 100644
--- a/app/src/main/java/org/thoughtcrime/securesms/service/webrtc/GroupPreJoinActionProcessor.java
+++ b/app/src/main/java/org/thoughtcrime/securesms/service/webrtc/GroupPreJoinActionProcessor.java
@@ -9,6 +9,7 @@ import org.signal.ringrtc.CallException;
 import org.signal.ringrtc.GroupCall;
 import org.signal.ringrtc.PeekInfo;
 import org.thoughtcrime.securesms.components.webrtc.BroadcastVideoSink;
+import org.thoughtcrime.securesms.components.webrtc.CallParticipantsState;
 import org.thoughtcrime.securesms.components.webrtc.EglBaseWrapper;
 import org.thoughtcrime.securesms.events.CallParticipant;
 import org.thoughtcrime.securesms.events.CallParticipantId;
@@ -149,7 +150,16 @@ public class GroupPreJoinActionProcessor extends GroupActionProcessor {
                                                                      CallParticipant.DeviceOrdinal.PRIMARY));
     }
 
-    return builder.build();
+    WebRtcServiceStateBuilder stateBuilder = builder.commit();
+
+    if (peekInfo.getDeviceCountExcludingPendingDevices() >= CallParticipantsState.PRE_JOIN_MUTE_THRESHOLD && currentState.getLocalDeviceState().isMicrophoneEnabled()) {
+      Log.i(tag, "Large call detected (" + peekInfo.getDeviceCountExcludingPendingDevices() + " participants), auto-muting microphone");
+      return stateBuilder.changeLocalDeviceState()
+                         .isMicrophoneEnabled(false)
+                         .build();
+    }
+
+    return stateBuilder.build();
   }
 
   @Override
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 287886dfd8..65814f3a59 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -2581,6 +2581,8 @@
     <string name="WebRtcCallView__s_remotely_muted_s">%1$s muted %2$s.</string>
     <!-- Alert message indicating that the local user joined a call on a second device and muted this one from the other one. -->
     <string name="WebRtcCallView__you_muted_yourself">You muted yourself from another device.</string>
+    <!-- Toast message shown when user is auto-muted because they are joining a large group call. -->
+    <string name="WebRtcCallView__youve_been_muted_large_group">You\'ve been muted because this call has many participants.</string>
 
     <!-- Error message when the developer added a button in the wrong place. -->
     <string name="WebRtcAudioOutputToggleButton_fragment_activity_error">A UI error occurred. Please report this error to the developers.</string>