diff --git a/telethon/tl/custom/participantpermissions.py b/telethon/tl/custom/participantpermissions.py
index 3b9f864b..a94cf0e4 100644
--- a/telethon/tl/custom/participantpermissions.py
+++ b/telethon/tl/custom/participantpermissions.py
@@ -79,6 +79,13 @@ class ParticipantPermissions:
         """
         return isinstance(self.participant, types.ChannelParticipantBanned)
 
+    @property
+    def is_left(self):
+        """
+        Whether the user left the chat.
+        """
+        return isinstance(self.participant, types.ChannelParticipantLeft)
+    
     @property
     def add_admins(self):
         """