diff --git a/CHANGELOG.md b/CHANGELOG.md
index 2dd5a500..628197b1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -17,6 +17,7 @@ and this project adheres to
 
 - ✨(frontend) enhance noise reduction with BBBA audio processing pipeline
 - 🚸(frontend) mute join notification sound in larger rooms
+- 🚸(frontend) mute participants by default when joining a large meeting
 
 ## [1.20.0] - 2026-06-12
 
diff --git a/src/backend/meet/settings.py b/src/backend/meet/settings.py
index 9fa2c1a0..05ce3edb 100755
--- a/src/backend/meet/settings.py
+++ b/src/backend/meet/settings.py
@@ -413,7 +413,10 @@ class Base(Configuration):
         ),
         "max_participants_for_sound": values.PositiveIntegerValue(
             5, environ_name="FRONTEND_MAX_PARTICIPANTS_FOR_SOUND", environ_prefix=None
-        )
+        ),
+        "auto_mute_on_join_threshold": values.PositiveIntegerValue(
+            50, environ_name="FRONTEND_AUTO_MUTE_ON_JOIN_THRESHOLD", environ_prefix=None
+        ),
     }
 
     # Mail
diff --git a/src/frontend/src/api/useConfig.ts b/src/frontend/src/api/useConfig.ts
index 1265b59e..943f2c38 100644
--- a/src/frontend/src/api/useConfig.ts
+++ b/src/frontend/src/api/useConfig.ts
@@ -56,6 +56,7 @@ export interface ApiConfig {
   }
   transcription_destination?: string
   max_participants_for_sound: number
+  auto_mute_on_join_threshold: number
 }
 
 const fetchConfig = (): Promise<ApiConfig> => {
diff --git a/src/frontend/src/features/notifications/NotificationType.ts b/src/frontend/src/features/notifications/NotificationType.ts
index 7eadc929..1475e9c2 100644
--- a/src/frontend/src/features/notifications/NotificationType.ts
+++ b/src/frontend/src/features/notifications/NotificationType.ts
@@ -1,4 +1,5 @@
 export enum NotificationType {
+  AutoMuteLargeRoom = 'autoMuteLargeRoom',
   ParticipantJoined = 'participantJoined',
   HandRaised = 'handRaised',
   ParticipantMuted = 'participantMuted',
diff --git a/src/frontend/src/features/notifications/components/ToastAutoMuteLargeRoom.tsx b/src/frontend/src/features/notifications/components/ToastAutoMuteLargeRoom.tsx
new file mode 100644
index 00000000..e72e8f9e
--- /dev/null
+++ b/src/frontend/src/features/notifications/components/ToastAutoMuteLargeRoom.tsx
@@ -0,0 +1,54 @@
+import { useToast } from '@react-aria/toast'
+import { useRef } from 'react'
+
+import { type ToastProps } from './Toast'
+import { VStack } from '@/styled-system/jsx'
+import { useTranslation } from 'react-i18next'
+import { Button } from '@/primitives'
+import { css } from '@/styled-system/css'
+import { StyledToastContainer } from './StyledToastContainer'
+import { useRoomContext } from '@livekit/components-react'
+
+export function ToastAutoMuteLargeRoom({
+  state,
+  ...props
+}: Readonly<ToastProps>) {
+  const room = useRoomContext()
+  const { t } = useTranslation('notifications', {
+    keyPrefix: 'autoMuteLargeRoom',
+  })
+  const ref = useRef(null)
+  const { toastProps, contentProps } = useToast(props, state, ref)
+  const toast = props.toast
+
+  const handleDismiss = async () => {
+    room.localParticipant
+      .setMicrophoneEnabled(true)
+      .finally(() => state.close(toast.key))
+  }
+
+  return (
+    <StyledToastContainer {...toastProps} ref={ref}>
+      <VStack
+        justify="start"
+        alignItems="self-start"
+        {...contentProps}
+        maxWidth="370px"
+        gap="0.75rem"
+        padding={14}
+      >
+        <p>{t('auto')}</p>
+        <Button
+          size="sm"
+          variant="text"
+          className={css({
+            color: 'primary.300',
+          })}
+          onPress={() => handleDismiss()}
+        >
+          {t('dismiss')}
+        </Button>
+      </VStack>
+    </StyledToastContainer>
+  )
+}
diff --git a/src/frontend/src/features/notifications/components/ToastRegion.tsx b/src/frontend/src/features/notifications/components/ToastRegion.tsx
index 64a3a321..45fb55fa 100644
--- a/src/frontend/src/features/notifications/components/ToastRegion.tsx
+++ b/src/frontend/src/features/notifications/components/ToastRegion.tsx
@@ -13,6 +13,7 @@ import { ToastAnyRecording } from './ToastAnyRecording'
 import { ToastRecordingSaving } from './ToastRecordingSaving'
 import { ToastPermissionsRemoved } from './ToastPermissionsRemoved'
 import { ToastRecordingRequest } from './ToastRecordingRequest'
+import { ToastAutoMuteLargeRoom } from './ToastAutoMuteLargeRoom'
 
 interface ToastRegionProps extends AriaToastRegionProps {
   state: ToastState<ToastData>
@@ -45,6 +46,11 @@ const renderToast = (
     case NotificationType.LowerHand:
       return <ToastLowerHand key={toast.key} toast={toast} state={state} />
 
+    case NotificationType.AutoMuteLargeRoom:
+      return (
+        <ToastAutoMuteLargeRoom key={toast.key} toast={toast} state={state} />
+      )
+
     case NotificationType.TranscriptionStarted:
     case NotificationType.TranscriptionStopped:
     case NotificationType.TranscriptionLimitReached:
diff --git a/src/frontend/src/features/notifications/utils.ts b/src/frontend/src/features/notifications/utils.ts
index 899ca5e0..a43dbe34 100644
--- a/src/frontend/src/features/notifications/utils.ts
+++ b/src/frontend/src/features/notifications/utils.ts
@@ -5,6 +5,15 @@ import type { Participant } from 'livekit-client'
 import type { NotificationPayload } from './NotificationPayload'
 import type { RecordingMode } from '@/features/recording'
 
+export const notifyAutoMutedOnJoin = () => {
+  toastQueue.add(
+    {
+      type: NotificationType.AutoMuteLargeRoom,
+    },
+    { timeout: NotificationDuration.ALERT }
+  )
+}
+
 export const showLowerHandToast = (
   participant: Participant,
   onClose: () => void
diff --git a/src/frontend/src/features/rooms/components/Conference.tsx b/src/frontend/src/features/rooms/components/Conference.tsx
index 35e37277..27ee3c10 100644
--- a/src/frontend/src/features/rooms/components/Conference.tsx
+++ b/src/frontend/src/features/rooms/components/Conference.tsx
@@ -1,4 +1,4 @@
-import { useEffect, useMemo, useState } from 'react'
+import { useEffect, useMemo, useRef, useState } from 'react'
 import { useQuery } from '@tanstack/react-query'
 import { useTranslation } from 'react-i18next'
 import {
@@ -33,6 +33,9 @@ import { useIsMobile } from '@/utils/useIsMobile'
 import { navigateTo } from '@/navigation/navigateTo'
 import { connectionObserverStore } from '@/stores/connectionObserver'
 import { PictureInPictureConference } from '@/features/pip/components/PictureInPictureConference'
+import { notifyAutoMutedOnJoin } from '@/features/notifications/utils'
+import { useSnapshot } from 'valtio'
+import { userPreferencesStore } from '@/stores/userPreferences'
 
 export const Conference = ({
   roomId,
@@ -57,6 +60,8 @@ export const Conference = ({
 
   const [isConnectionWarmedUp, setIsConnectionWarmedUp] = useState(false)
 
+  const userPreferencesSnap = useSnapshot(userPreferencesStore)
+
   const {
     mutateAsync: createRoom,
     status: createStatus,
@@ -173,6 +178,8 @@ export const Conference = ({
 
   const isMobile = useIsMobile()
 
+  const hasAutoMutedRef = useRef(false)
+
   /*
    * Ensure stable WebSocket connection URL. This is critical for legacy browser compatibility
    * (Firefox <124, Chrome <125, Edge <125) where HTTPS URLs in WebSocket() constructor
@@ -228,6 +235,19 @@ export const Conference = ({
           onError={(e) => {
             posthog.captureException(e)
           }}
+          onConnected={async () => {
+            if (!apiConfig) return
+            if (
+              userPreferencesSnap.is_auto_mute_large_room_enabled &&
+              !hasAutoMutedRef.current &&
+              userConfig.audioEnabled &&
+              room.numParticipants > apiConfig.auto_mute_on_join_threshold
+            ) {
+              hasAutoMutedRef.current = true
+              await room.localParticipant.setMicrophoneEnabled(false)
+              notifyAutoMutedOnJoin()
+            }
+          }}
           onDisconnected={(e) => {
             const metadata = {
               room_id: roomId,
diff --git a/src/frontend/src/features/settings/components/tabs/GeneralTab.tsx b/src/frontend/src/features/settings/components/tabs/GeneralTab.tsx
index e07d357c..d86bfdcc 100644
--- a/src/frontend/src/features/settings/components/tabs/GeneralTab.tsx
+++ b/src/frontend/src/features/settings/components/tabs/GeneralTab.tsx
@@ -39,6 +39,19 @@ export const GeneralTab = ({ id }: GeneralTabProps) => {
           fullWidth: true,
         }}
       />
+      <Field
+        type="switch"
+        label={t('preferences.autoMuteLargeRoom.label')}
+        description={t('preferences.autoMuteLargeRoom.description')}
+        isSelected={userPreferencesSnap.is_auto_mute_large_room_enabled}
+        onChange={(value) =>
+          (userPreferencesStore.is_auto_mute_large_room_enabled = value)
+        }
+        wrapperProps={{
+          noMargin: true,
+          fullWidth: true,
+        }}
+      />
     </TabPanel>
   )
 }
diff --git a/src/frontend/src/locales/de/notifications.json b/src/frontend/src/locales/de/notifications.json
index 356ed2a6..67f495b6 100644
--- a/src/frontend/src/locales/de/notifications.json
+++ b/src/frontend/src/locales/de/notifications.json
@@ -14,6 +14,10 @@
     "auto": "Du hast begonnen zu sprechen – deine Hand wird daher automatisch gesenkt.",
     "dismiss": "Hand oben lassen"
   },
+  "autoMuteLargeRoom": {
+    "auto": "Sie haben an einer großen Besprechung teilgenommen. Ihr Mikrofon wurde automatisch stummgeschaltet.",
+    "dismiss": "Stummschaltung aufheben"
+  },
   "reaction": {
     "description": "{{name}} hat mit {{emoji}} reagiert"
   },
diff --git a/src/frontend/src/locales/de/settings.json b/src/frontend/src/locales/de/settings.json
index 8c13a096..9dfaffd8 100644
--- a/src/frontend/src/locales/de/settings.json
+++ b/src/frontend/src/locales/de/settings.json
@@ -12,6 +12,10 @@
     "idleDisconnectModal": {
       "label": "Meetings ohne Teilnehmende verlassen",
       "description": "Meetings nach einigen Minuten automatisch verlassen, wenn keine andere Person beitritt"
+    },
+    "autoMuteLargeRoom": {
+      "label": "Mikrofon automatisch stummschalten",
+      "description": "Dein Mikrofon wird automatisch stummgeschaltet, wenn du an einer großen Besprechung teilnimmst."
     }
   },
   "audio": {
diff --git a/src/frontend/src/locales/en/notifications.json b/src/frontend/src/locales/en/notifications.json
index 665bb94d..77d724bd 100644
--- a/src/frontend/src/locales/en/notifications.json
+++ b/src/frontend/src/locales/en/notifications.json
@@ -14,6 +14,10 @@
     "auto": "It seems you have started speaking, so your hand will be lowered.",
     "dismiss": "Keep hand raised"
   },
+  "autoMuteLargeRoom": {
+    "auto": "You have joined a large meeting. Your microphone has been automatically muted.",
+    "dismiss": "Unmute"
+  },
   "reaction": {
     "description": "{{name}} reacted with {{emoji}}"
   },
diff --git a/src/frontend/src/locales/en/settings.json b/src/frontend/src/locales/en/settings.json
index ff79348d..7f79fcd7 100644
--- a/src/frontend/src/locales/en/settings.json
+++ b/src/frontend/src/locales/en/settings.json
@@ -12,6 +12,10 @@
     "idleDisconnectModal": {
       "label": "Leave calls with no participants",
       "description": "Automatically leaves a call after a few minutes if no other participant joins"
+    },
+    "autoMuteLargeRoom": {
+      "label": "Automatically mute my microphone",
+      "description": "Automatically mute your microphone when joining a large meeting."
     }
   },
   "audio": {
diff --git a/src/frontend/src/locales/fr/notifications.json b/src/frontend/src/locales/fr/notifications.json
index 28a65e5f..0a84d453 100644
--- a/src/frontend/src/locales/fr/notifications.json
+++ b/src/frontend/src/locales/fr/notifications.json
@@ -14,6 +14,10 @@
     "auto": "Il semblerait que vous ayez pris la parole, donc la main va être baissée.",
     "dismiss": "Laisser la main levée"
   },
+  "autoMuteLargeRoom": {
+    "auto": "Vous venez de rejoindre une grande réunion. Votre micro a été automatiquement coupé.",
+    "dismiss": "Rétablir le micro"
+  },
   "reaction": {
     "description": "{{name}} a reagi avec {{emoji}}"
   },
diff --git a/src/frontend/src/locales/fr/settings.json b/src/frontend/src/locales/fr/settings.json
index 1e63c6bb..072c3ff4 100644
--- a/src/frontend/src/locales/fr/settings.json
+++ b/src/frontend/src/locales/fr/settings.json
@@ -12,6 +12,10 @@
     "idleDisconnectModal": {
       "label": "Quitter les appels sans autre participant",
       "description": "Vous fait quitter un appel au bout de quelques minutes si aucun autre participant ne vous rejoint"
+    },
+    "autoMuteLargeRoom": {
+      "label": "Couper automatiquement mon micro",
+      "description": "Coupe automatiquement votre micro lorsque vous rejoignez une réunion de grande taille."
     }
   },
   "audio": {
diff --git a/src/frontend/src/locales/nl/notifications.json b/src/frontend/src/locales/nl/notifications.json
index 74778286..a90cd56f 100644
--- a/src/frontend/src/locales/nl/notifications.json
+++ b/src/frontend/src/locales/nl/notifications.json
@@ -14,6 +14,10 @@
     "auto": "Het lijkt erop dat u bent begonnen te spreken, dus we laten uw hand zakken.",
     "dismiss": "Houdt uw hand opgestoken"
   },
+  "autoMuteLargeRoom": {
+    "auto": "U bent zojuist lid geworden van een grote vergadering. Uw microfoon is automatisch gedempt.",
+    "dismiss": "Microfoon inschakelen"
+  },
   "reaction": {
     "description": "{{name}} reageerde met {{emoji}}"
   },
diff --git a/src/frontend/src/locales/nl/settings.json b/src/frontend/src/locales/nl/settings.json
index b7c023db..6d4a71d0 100644
--- a/src/frontend/src/locales/nl/settings.json
+++ b/src/frontend/src/locales/nl/settings.json
@@ -12,6 +12,10 @@
     "idleDisconnectModal": {
       "label": "Verlaat oproepen zonder deelnemers",
       "description": "Verlaat automatisch een oproep na een paar minuten als geen andere deelnemer meedoet"
+    },
+    "autoMuteLargeRoom": {
+      "label": "Mijn microfoon automatisch dempen",
+      "description": "Uw microfoon wordt automatisch gedempt wanneer u deelneemt aan een grote vergadering."
     }
   },
   "audio": {
diff --git a/src/frontend/src/stores/userPreferences.ts b/src/frontend/src/stores/userPreferences.ts
index ca520790..0d19e1fd 100644
--- a/src/frontend/src/stores/userPreferences.ts
+++ b/src/frontend/src/stores/userPreferences.ts
@@ -3,10 +3,12 @@ import { STORAGE_KEYS } from '@/utils/storageKeys'
 
 type State = {
   is_idle_disconnect_modal_enabled: boolean
+  is_auto_mute_large_room_enabled: boolean
 }
 
 const DEFAULT_STATE = {
   is_idle_disconnect_modal_enabled: true,
+  is_auto_mute_large_room_enabled: true,
 }
 
 function getUserPreferencesState(): State {