diff --git a/src/components/structures/MatrixChat.tsx b/src/components/structures/MatrixChat.tsx
index 9ebfa17c82..241e5d580b 100644
--- a/src/components/structures/MatrixChat.tsx
+++ b/src/components/structures/MatrixChat.tsx
@@ -1180,12 +1180,8 @@ export default class MatrixChat extends React.PureComponent<IProps, IState> {
             button: _t("Leave"),
             onFinished: (shouldLeave) => {
                 if (shouldLeave) {
-                    const d = leaveRoomBehaviour(roomId);
+                    leaveRoomBehaviour(roomId);
 
-                    // FIXME: controller shouldn't be loading a view :(
-                    const modal = Modal.createDialog(Spinner, null, 'mx_Dialog_spinner');
-
-                    d.finally(() => modal.close());
                     dis.dispatch({
                         action: "after_leave_room",
                         room_id: roomId,
diff --git a/src/utils/membership.ts b/src/utils/membership.ts
index 1a120e08b3..2b31737dde 100644
--- a/src/utils/membership.ts
+++ b/src/utils/membership.ts
@@ -16,14 +16,16 @@ limitations under the License.
 
 import { Room } from "matrix-js-sdk/src/models/room";
 import { sleep } from "matrix-js-sdk/src/utils";
+import { EventStatus } from "matrix-js-sdk/src/models/event";
 
 import { MatrixClientPeg } from "../MatrixClientPeg";
 import { _t } from "../languageHandler";
-import Modal from "../Modal";
+import Modal, { IHandle } from "../Modal";
 import ErrorDialog from "../components/views/dialogs/ErrorDialog";
 import React from "react";
 import dis from "../dispatcher/dispatcher";
 import RoomViewStore from "../stores/RoomViewStore";
+import Spinner from "../components/views/elements/Spinner";
 
 /**
  * Approximation of a membership status for a given room.
@@ -85,7 +87,12 @@ export function isJoinedOrNearlyJoined(membership: string): boolean {
     return effective === EffectiveMembership.Join || effective === EffectiveMembership.Invite;
 }
 
-export async function leaveRoomBehaviour(roomId: string, retry = true) {
+export async function leaveRoomBehaviour(roomId: string, retry = true, spinner = true) {
+    let spinnerModal: IHandle<any>;
+    if (spinner) {
+        spinnerModal = Modal.createDialog(Spinner, null, 'mx_Dialog_spinner');
+    }
+
     const cli = MatrixClientPeg.get();
     let leavingAllVersions = true;
     const history = cli.getRoomUpgradeHistory(roomId);
@@ -98,6 +105,26 @@ export async function leaveRoomBehaviour(roomId: string, retry = true) {
         }
     }
 
+    const room = cli.getRoom(roomId);
+    // await any queued messages being sent so that they do not fail
+    await Promise.all(room.getPendingEvents().filter(ev => {
+        return [EventStatus.QUEUED, EventStatus.ENCRYPTING, EventStatus.SENDING].includes(ev.status);
+    }).map(ev => new Promise<void>((resolve, reject) => {
+        const handler = () => {
+            if (ev.status === EventStatus.NOT_SENT) {
+                spinnerModal?.close();
+                reject(ev.error);
+            }
+
+            if (!ev.status || ev.status === EventStatus.SENT) {
+                ev.off("Event.status", handler);
+                resolve();
+            }
+        };
+
+        ev.on("Event.status", handler);
+    })));
+
     let results: { [roomId: string]: Error & { errcode?: string, message: string, data?: Record<string, any> } } = {};
     if (!leavingAllVersions) {
         try {
@@ -118,10 +145,12 @@ export async function leaveRoomBehaviour(roomId: string, retry = true) {
         const limitExceededError = Object.values(results).find(e => e?.errcode === "M_LIMIT_EXCEEDED");
         if (limitExceededError) {
             await sleep(limitExceededError.data.retry_after_ms ?? 100);
-            return leaveRoomBehaviour(roomId, false);
+            return leaveRoomBehaviour(roomId, false, false);
         }
     }
 
+    spinnerModal?.close();
+
     const errors = Object.entries(results).filter(r => !!r[1]);
     if (errors.length > 0) {
         const messages = [];