diff --git a/crates/matrix-sdk-base/src/sliding_sync/mod.rs b/crates/matrix-sdk-base/src/sliding_sync/mod.rs
index 1f97eb1f526..77a52b702e6 100644
--- a/crates/matrix-sdk-base/src/sliding_sync/mod.rs
+++ b/crates/matrix-sdk-base/src/sliding_sync/mod.rs
@@ -999,6 +999,7 @@ mod tests {
         assert!(sync_resp.rooms.join.contains_key(room_id));
         assert!(!sync_resp.rooms.leave.contains_key(room_id));
         assert!(!sync_resp.rooms.invite.contains_key(room_id));
+        assert!(!sync_resp.rooms.knocked.contains_key(room_id));
     }
 
     #[async_test]
@@ -1084,6 +1085,76 @@ mod tests {
         assert_eq!(client_room.compute_display_name().await.unwrap().to_string(), "The Name");
     }
 
+    #[async_test]
+    async fn test_knocked_room_membership_event() {
+        // Given a logged-in client,
+        let client = logged_in_base_client(None).await;
+        let room_id = room_id!("!r:e.uk");
+        let user_id = client.session_meta().unwrap().user_id.to_owned();
+
+        // When the room is properly set as knocked with the current user id as state
+        // key,
+        let mut room = http::response::Room::new();
+        set_room_knocked(&mut room, &user_id);
+
+        let response = response_with_room(room_id, room);
+        client.process_sliding_sync(&response, &(), true).await.expect("Failed to process sync");
+
+        // The room is knocked.
+        let client_room = client.get_room(room_id).expect("No room found");
+        assert_eq!(client_room.state(), RoomState::Knocked);
+    }
+
+    #[async_test]
+    async fn test_knocked_room_membership_event_with_wrong_state_key() {
+        // Given a logged-in client,
+        let client = logged_in_base_client(None).await;
+        let room_id = room_id!("!r:e.uk");
+        let user_id = user_id!("@w:e.uk");
+
+        // When the room is set as knocked with a random user id as state key,
+        let mut room = http::response::Room::new();
+        set_room_knocked(&mut room, &user_id);
+
+        let response = response_with_room(room_id, room);
+        client.process_sliding_sync(&response, &(), true).await.expect("Failed to process sync");
+
+        // The room is invited since the membership event doesn't belong to the current
+        // user.
+        let client_room = client.get_room(room_id).expect("No room found");
+        assert_eq!(client_room.state(), RoomState::Invited);
+    }
+
+    #[async_test]
+    async fn test_unknown_room_membership_event_in_invite_state() {
+        // Given a logged-in client,
+        let client = logged_in_base_client(None).await;
+        let room_id = room_id!("!r:e.uk");
+        let user_id = client.session_meta().unwrap().user_id.to_owned();
+
+        // When the room has the wrong membership state in its invite_state
+        let mut room = http::response::Room::new();
+        let event = Raw::new(&json!({
+            "type": "m.room.member",
+            "sender": user_id,
+            "content": {
+                "is_direct": true,
+                "membership": "join",
+            },
+            "state_key": user_id,
+        }))
+        .expect("Failed to make raw event")
+        .cast();
+        room.invite_state = Some(vec![event]);
+
+        let response = response_with_room(room_id, room);
+        client.process_sliding_sync(&response, &(), true).await.expect("Failed to process sync");
+
+        // The room is marked as invited.
+        let client_room = client.get_room(room_id).expect("No room found");
+        assert_eq!(client_room.state(), RoomState::Invited);
+    }
+
     #[async_test]
     async fn test_left_a_room_from_required_state_event() {
         // Given a logged-in client
@@ -1114,6 +1185,7 @@ mod tests {
         assert!(!sync_resp.rooms.join.contains_key(room_id));
         assert!(sync_resp.rooms.leave.contains_key(room_id));
         assert!(!sync_resp.rooms.invite.contains_key(room_id));
+        assert!(!sync_resp.rooms.knocked.contains_key(room_id));
     }
 
     #[async_test]
@@ -1155,6 +1227,7 @@ mod tests {
             assert!(!sync_resp.rooms.join.contains_key(room_id));
             assert!(sync_resp.rooms.leave.contains_key(room_id));
             assert!(!sync_resp.rooms.invite.contains_key(room_id));
+            assert!(!sync_resp.rooms.knocked.contains_key(room_id));
         }
     }
 
@@ -2597,6 +2670,25 @@ mod tests {
         ));
     }
 
+    fn set_room_knocked(room: &mut http::response::Room, knocker: &UserId) {
+        // MSC3575 shows an almost-empty event to indicate that we are invited to a
+        // room. Just the type is supplied.
+
+        let evt = Raw::new(&json!({
+            "type": "m.room.member",
+            "sender": knocker,
+            "content": {
+                "is_direct": true,
+                "membership": "knock",
+            },
+            "state_key": knocker,
+        }))
+        .expect("Failed to make raw event")
+        .cast();
+
+        room.invite_state = Some(vec![evt]);
+    }
+
     fn set_room_joined(room: &mut http::response::Room, user_id: &UserId) {
         room.required_state.push(make_membership_event(user_id, MembershipState::Join));
     }