diff --git a/spec/unit/content-helpers.spec.ts b/spec/unit/content-helpers.spec.ts
index 1993b832ca..911cd69e34 100644
--- a/spec/unit/content-helpers.spec.ts
+++ b/spec/unit/content-helpers.spec.ts
@@ -211,13 +211,11 @@ describe("Topic content helpers", () => {
         it("creates an empty event when the topic is falsey", () => {
             expect(makeTopicContent(undefined)).toEqual({
                 topic: undefined,
-                [M_TOPIC.name]: [
-                ],
+                [M_TOPIC.name]: [],
             });
             expect(makeTopicContent(null)).toEqual({
                 topic: null,
-                [M_TOPIC.name]: [
-                ],
+                [M_TOPIC.name]: [],
             });
         });
     });
diff --git a/src/@types/state_events.ts b/src/@types/state_events.ts
index d570c5a129..a580c41c43 100644
--- a/src/@types/state_events.ts
+++ b/src/@types/state_events.ts
@@ -90,7 +90,7 @@ export interface RoomNameEventContent {
 }
 
 export interface RoomTopicEventContent {
-    topic: string;
+    topic: string | undefined | null;
 }
 
 export interface RoomAvatarEventContent {
diff --git a/src/client.ts b/src/client.ts
index 5e1c8deee3..c05e6a1a1e 100644
--- a/src/client.ts
+++ b/src/client.ts
@@ -4490,11 +4490,13 @@ export class MatrixClient extends TypedEventEmitter<EmittedEvents, ClientEventHa
     }
 
     /**
+     * @param roomId - The room to update the topic in.
+     * @param topic - The plaintext topic. May be empty to remove the topic.
      * @param htmlTopic - Optional.
      * @returns Promise which resolves: TODO
      * @returns Rejects: with an error response.
      */
-    public setRoomTopic(roomId: string, topic: string, htmlTopic?: string): Promise<ISendEventResponse> {
+    public setRoomTopic(roomId: string, topic?: string, htmlTopic?: string): Promise<ISendEventResponse> {
         const content = ContentHelpers.makeTopicContent(topic, htmlTopic);
         return this.sendStateEvent(roomId, EventType.RoomTopic, content);
     }
diff --git a/src/content-helpers.ts b/src/content-helpers.ts
index 32020e764d..fb27b98cb9 100644
--- a/src/content-helpers.ts
+++ b/src/content-helpers.ts
@@ -14,6 +14,8 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
+import { Optional } from "matrix-events-sdk";
+
 import { MBeaconEventContent, MBeaconInfoContent, MBeaconInfoEventContent } from "./@types/beacon.ts";
 import { MsgType } from "./@types/event.ts";
 import { M_TEXT, REFERENCE_RELATION } from "./@types/extensible_events.ts";
@@ -31,7 +33,6 @@ import {
 } from "./@types/location.ts";
 import { MRoomTopicEventContent, MTopicContent, M_TOPIC } from "./@types/topic.ts";
 import { RoomMessageEventContent } from "./@types/events.ts";
-import { Optional } from "matrix-events-sdk";
 
 /**
  * Generates the content for a HTML Message event