diff --git a/src/Notifier.ts b/src/Notifier.ts
index fbe3add75b..35362738ca 100644
--- a/src/Notifier.ts
+++ b/src/Notifier.ts
@@ -32,6 +32,8 @@ import {
 } from "matrix-js-sdk/src/matrix";
 import { logger } from "matrix-js-sdk/src/logger";
 import { PermissionChanged as PermissionChangedEvent } from "@matrix-org/analytics-events/types/typescript/PermissionChanged";
+// eslint-disable-next-line no-restricted-imports
+import { MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
 
 import { MatrixClientPeg } from "./MatrixClientPeg";
 import { PosthogAnalytics } from "./PosthogAnalytics";
@@ -505,10 +507,16 @@ class NotifierClass {
      * Some events require special handling such as showing in-app toasts
      */
     private performCustomEventHandling(ev: MatrixEvent): void {
+        const cli = MatrixClientPeg.safeGet();
+        const room = cli.getRoom(ev.getRoomId());
+        const thisUserHasConnectedDevice =
+            room && MatrixRTCSession.callMembershipsForRoom(room).some((m) => m.sender === cli.getUserId());
+
         if (
             EventType.CallNotify === ev.getType() &&
             SettingsStore.getValue("feature_group_calls") &&
-            (ev.getAge() ?? 0) < 10000
+            (ev.getAge() ?? 0) < 10000 &&
+            !thisUserHasConnectedDevice
         ) {
             const content = ev.getContent();
             const roomId = ev.getRoomId();
diff --git a/test/Notifier-test.ts b/test/Notifier-test.ts
index a47b6cf5a4..224de7d8eb 100644
--- a/test/Notifier-test.ts
+++ b/test/Notifier-test.ts
@@ -26,6 +26,10 @@ import {
     SyncState,
 } from "matrix-js-sdk/src/matrix";
 import { waitFor } from "@testing-library/react";
+// eslint-disable-next-line no-restricted-imports
+import { MatrixRTCSession } from "matrix-js-sdk/src/matrixrtc/MatrixRTCSession";
+// eslint-disable-next-line no-restricted-imports
+import { CallMembership } from "matrix-js-sdk/src/matrixrtc/CallMembership";
 
 import BasePlatform from "../src/BasePlatform";
 import Notifier from "../src/Notifier";
@@ -139,6 +143,11 @@ describe("Notifier", () => {
             getRoom: jest.fn(),
             getPushActionsForEvent: jest.fn(),
             supportsThreads: jest.fn().mockReturnValue(false),
+            matrixRTC: {
+                on: jest.fn(),
+                off: jest.fn(),
+                getRoomSession: jest.fn(),
+            },
         });
 
         mockClient.pushRules = {
@@ -455,6 +464,35 @@ describe("Notifier", () => {
             expect(ToastStore.sharedInstance().addOrReplaceToast).not.toHaveBeenCalled();
         });
 
+        it("should not show toast when group call is already connected", () => {
+            setGroupCallsEnabled(true);
+            const spyCallMemberships = jest.spyOn(MatrixRTCSession, "callMembershipsForRoom").mockReturnValue([
+                new CallMembership(
+                    mkEvent({
+                        event: true,
+                        room: testRoom.roomId,
+                        user: userId,
+                        type: EventType.GroupCallMemberPrefix,
+                        content: {},
+                    }),
+                    {
+                        call_id: "123",
+                        application: "m.call",
+                        focus_active: { type: "livekit" },
+                        foci_preferred: [],
+                        device_id: "DEVICE",
+                    },
+                ),
+            ]);
+
+            const roomSession = MatrixRTCSession.roomSessionForRoom(mockClient, testRoom);
+
+            mockClient.matrixRTC.getRoomSession.mockReturnValue(roomSession);
+            emitCallNotifyEvent();
+            expect(ToastStore.sharedInstance().addOrReplaceToast).not.toHaveBeenCalled();
+            spyCallMemberships.mockRestore();
+        });
+
         it("should not show toast when calling with non-group call event", () => {
             setGroupCallsEnabled(true);