diff --git a/src/SynapseAdminApis.ts b/src/SynapseAdminApis.ts
index 84bcdecd..ceba26f4 100644
--- a/src/SynapseAdminApis.ts
+++ b/src/SynapseAdminApis.ts
@@ -479,4 +479,14 @@ export class SynapseAdminApis {
     public async makeRoomAdmin(roomId: string, userId?: string): Promise<void> {
         return this.client.doRequest("POST", `/_synapse/admin/v1/rooms/${encodeURIComponent(roomId)}/make_room_admin`, {}, { user_id: userId });
     }
+
+    /**
+     * Joins a local user account to a room.
+     * @param roomId The room to make the user join.
+     * @param UserId The user to join into the room.
+     * @returns Resolves when complete.
+     */
+    public async joinUserToRoom(roomId: string, userId: string): Promise<void> {
+        return this.client.doRequest("POST", `/_synapse/admin/v1/join/${encodeURIComponent(roomId)}`, {}, { user_id: userId });
+    }
 }
diff --git a/test/SynapseAdminApisTest.ts b/test/SynapseAdminApisTest.ts
index b9d9f5f6..93ed7e18 100644
--- a/test/SynapseAdminApisTest.ts
+++ b/test/SynapseAdminApisTest.ts
@@ -531,5 +531,22 @@ describe('SynapseAdminApis', () => {
                 await Promise.all([client.makeRoomAdmin(roomId, userId), http.flushAllExpected()]);
             });
         });
+
+        describe('joinUserToRoom', () => {
+            it('should call the right endpoint', async () => {
+                const { client, http, hsUrl } = createTestSynapseAdminClient();
+
+                const roomId = "!room:example.org";
+                const userId = "@alice:example.org";
+
+                http.when("POST", "/_synapse/admin/v1/join").respond(200, (path, content, req) => {
+                    expect(content).toMatchObject({ user_id: userId });
+                    expect(path).toEqual(`${hsUrl}/_synapse/admin/v1/join/${encodeURIComponent(roomId)}`);
+                    return {};
+                });
+
+                await Promise.all([client.joinUserToRoom(roomId, userId), http.flushAllExpected()]);
+            });
+        });
     });
 });