diff --git a/test/test-utils/test-utils.ts b/test/test-utils/test-utils.ts
index 66ca40e482..7fb434bf29 100644
--- a/test/test-utils/test-utils.ts
+++ b/test/test-utils/test-utils.ts
@@ -12,6 +12,7 @@ import {
     EventTimeline,
     RoomState,
     EventType,
+    IEventRelation,
 } from 'matrix-js-sdk';
 
 import { MatrixClientPeg as peg } from '../../src/MatrixClientPeg';
@@ -259,6 +260,12 @@ export function mkMembership(opts: MakeEventPassThruProps & {
     return e;
 }
 
+export type MessageEventProps = MakeEventPassThruProps & {
+    room: Room["roomId"];
+    relatesTo?: IEventRelation;
+    msg?: string;
+};
+
 /**
  * Create an m.room.message event.
  * @param {Object} opts Values for the message
@@ -269,20 +276,20 @@ export function mkMembership(opts: MakeEventPassThruProps & {
  * @param {string=} opts.msg Optional. The content.body for the event.
  * @return {Object|MatrixEvent} The event
  */
-export function mkMessage(opts: MakeEventPassThruProps & {
-    room: Room["roomId"];
-    msg?: string;
-}): MatrixEvent {
+export function mkMessage({
+    msg, relatesTo, ...opts
+}: MessageEventProps): MatrixEvent {
     if (!opts.room || !opts.user) {
         throw new Error("Missing .room or .user from options");
     }
-    const message = opts.msg ?? "Random->" + Math.random();
+    const message = msg ?? "Random->" + Math.random();
     const event: MakeEventProps = {
         ...opts,
         type: "m.room.message",
         content: {
             msgtype: "m.text",
             body: message,
+            ['m.relates_to']: relatesTo,
         },
     };
 
diff --git a/test/test-utils/threads.ts b/test/test-utils/threads.ts
new file mode 100644
index 0000000000..1d250d07e9
--- /dev/null
+++ b/test/test-utils/threads.ts
@@ -0,0 +1,93 @@
+
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+import { IUnsigned, MatrixClient, MatrixEvent, Room } from "matrix-js-sdk";
+import { Thread } from "matrix-js-sdk/src/models/thread";
+
+import { mkMessage, MessageEventProps } from "./test-utils";
+
+export const makeThreadEvent = ({ rootEventId, replyToEventId, ...props }: MessageEventProps & {
+    rootEventId: string; replyToEventId: string;
+}): MatrixEvent => mkMessage({
+    ...props,
+    relatesTo: {
+        event_id: rootEventId,
+        rel_type: "io.element.thread",
+        ['m.in_reply_to']: {
+            event_id: replyToEventId,
+        },
+    },
+});
+
+type MakeThreadEventsProps = {
+    roomId: Room["roomId"];
+    // root message user id
+    authorId: string;
+    // user ids of thread replies
+    // cycled through until thread length is fulfilled
+    participantUserIds: string[];
+    // number of messages in the thread, root message included
+    // optional, default 2
+    length?: number;
+    ts?: number;
+    // provide to set current_user_participated accurately
+    currentUserId?: string;
+};
+
+export const makeThreadEvents = ({
+    roomId, authorId, participantUserIds, length = 2, ts = 1, currentUserId,
+}): { rootEvent: MatrixEvent, events: MatrixEvent[] } => {
+    const rootEvent = mkMessage({
+        user: authorId,
+        event: true,
+        room: roomId,
+        msg: 'root event message',
+        ts,
+    });
+
+    const rootEventId = rootEvent.getId();
+    const events = [rootEvent];
+
+    for (let i = 1; i < length; i++) {
+        const prevEvent = events[i - 1];
+        const replyToEventId = prevEvent.getId();
+        const user = participantUserIds[i % participantUserIds.length];
+        events.push(makeThreadEvent({
+            user,
+            room: roomId,
+            event: true,
+            msg: `reply ${i} by ${user}`,
+            rootEventId,
+            replyToEventId,
+            // replies are 1ms after each other
+            ts: ts + i,
+        }));
+    }
+
+    rootEvent.setUnsigned({
+        latest_event: events[events.length - 1],
+        count: length,
+        current_user_participated: [...participantUserIds, authorId].includes(currentUserId),
+    } as IUnsigned);
+
+    return { rootEvent, events };
+};
+
+export const makeThread = (client: MatrixClient, room: Room, props: MakeThreadEventsProps): Thread => {
+    const { rootEvent, events } = makeThreadEvents(props);
+    return new Thread(rootEvent, { initialEvents: events, room, client });
+};