diff --git a/telethon/client/chats.py b/telethon/client/chats.py
index 74111ffb..0823bf6a 100644
--- a/telethon/client/chats.py
+++ b/telethon/client/chats.py
@@ -847,6 +847,9 @@ class ChatMethods:
         """
         entity = await self.get_input_entity(entity)
         user = await self.get_input_entity(user)
+        if isinstance(user, types.InputPeerSelf):
+            raise ValueError('You cannot admin yourself')
+
         if not isinstance(user, types.InputPeerUser):
             raise ValueError('You must pass a user entity')
 
@@ -996,6 +999,9 @@ class ChatMethods:
             ))
 
         user = await self.get_input_entity(user)
+        if isinstance(user, types.InputPeerSelf):
+            raise ValueError("You cannot restrict yourself")
+
         if not isinstance(user, types.InputPeerUser):
             raise ValueError('You must pass a user entity')