diff --git a/README.md b/README.md
index 8a3b9f61..249a48cd 100644
--- a/README.md
+++ b/README.md
@@ -79,7 +79,7 @@ The bridge does not do this automatically.
     * [ ] Inviting Matrix users who have logged in to Telegram
     * [ ] Kicking
     * [ ] Joining (once room aliases have been implemented)
-    * [ ] Leaving
+    * [x] Leaving
   * [ ] Room metadata changes
 * Telegram → Matrix
   * [x] Plaintext messages
diff --git a/mautrix_telegram/matrix.py b/mautrix_telegram/matrix.py
index 8bdee033..02d80dc2 100644
--- a/mautrix_telegram/matrix.py
+++ b/mautrix_telegram/matrix.py
@@ -126,7 +126,10 @@ class MatrixHandler:
 
     def handle_part(self, room, user):
         self.log.debug(f"{user} left {room}")
-        # user = User.get_by_mxid(user, create=False)
+        user = User.get_by_mxid(user, create=False)
+        portal = Portal.get_by_mxid(room)
+        if portal and user.logged_in:
+            portal.leave_matrix(user)
 
     def is_command(self, message):
         text = message.get("body", "")
diff --git a/mautrix_telegram/portal.py b/mautrix_telegram/portal.py
index ff20afff..4b4221ea 100644
--- a/mautrix_telegram/portal.py
+++ b/mautrix_telegram/portal.py
@@ -16,9 +16,10 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 from telethon.tl.functions.messages import (GetFullChatRequest, EditChatAdminRequest,
                                             CreateChatRequest, AddChatUserRequest,
-                                            ExportChatInviteRequest)
+                                            ExportChatInviteRequest, DeleteChatUserRequest)
 from telethon.tl.functions.channels import (GetParticipantsRequest, CreateChannelRequest,
-                                            InviteToChannelRequest, ExportInviteRequest)
+                                            InviteToChannelRequest, ExportInviteRequest,
+                                            LeaveChannelRequest)
 from telethon.errors.rpc_error_list import ChatAdminRequiredError, LocationInvalidError
 from telethon.tl.types import *
 from PIL import Image
@@ -267,6 +268,17 @@ class Portal:
             file_name = f"matrix_upload{mimetypes.guess_extension(mime)}"
         return file_name, None if file_name == body else body
 
+    def leave_matrix(self, user):
+        if self.peer_type == "user":
+            self.main_intent.leave_room(self.mxid)
+            self.delete()
+            del self.by_tgid[self.tgid_full]
+            del self.by_mxid[self.mxid]
+        elif self.peer_type == "chat":
+            user.client(DeleteChatUserRequest(chat_id=self.tgid, user_id=InputUserSelf()))
+        elif self.peer_type == "channel":
+            user.client(LeaveChannelRequest(channel=user.client.get_input_entity(self.peer)))
+
     def handle_matrix_message(self, sender, message, event_id):
         type = message["msgtype"]
         if type in {"m.text", "m.emote"}:
@@ -581,7 +593,7 @@ class Portal:
         existing = DBPortal.query.get(self.tgid_full)
         if existing:
             self.db.object_session(existing).delete(existing)
-        self.by_tgid[self.tgid_full] = None
+        del self.by_tgid[self.tgid_full]
         self.tgid = new_id
         self.by_tgid[self.tgid_full] = self
         self.save()
@@ -592,6 +604,7 @@ class Portal:
 
     def delete(self):
         self.db.delete(self.to_db())
+        self.db.commit()
 
     @classmethod
     def from_db(cls, db_portal):
diff --git a/mautrix_telegram/user.py b/mautrix_telegram/user.py
index 9a729852..69eb0e1f 100644
--- a/mautrix_telegram/user.py
+++ b/mautrix_telegram/user.py
@@ -210,8 +210,9 @@ class User:
         elif isinstance(update, (UpdateChatAdmins, UpdateChatParticipantAdmin)):
             self.update_admin(update)
         elif isinstance(update, UpdateChatParticipants):
-            portal = po.Portal.get_by_tgid(update.participants.chat_id, peer_type="chat")
-            portal.update_telegram_participants(update.participants.participants)
+            portal = po.Portal.get_by_tgid(update.participants.chat_id, peer_type=None)
+            if portal and portal.mxid:
+                portal.update_telegram_participants(update.participants.participants)
         else:
             self.log.debug("Unhandled update: %s", update)