discord/ext/commands/bot.py

@@ -529,6 +529,9 @@ class BotBase(GroupMixin):
 
         cog = cog._inject(self)
         self.__cogs[cog.__cog_name__] = cog
+        if cog.aliases:
+            for alias in cog.aliases:
+                self.__cogs[alias] = cog
 
     def get_cog(self, name):
         """Gets the cog instance requested.
@@ -567,6 +570,10 @@ class BotBase(GroupMixin):
         if cog is None:
             return
 
+        if cog.aliases:
+            for alias in cog.aliases:
+                self.__cogs.pop(alias)
+
         help_command = self._help_command
         if help_command and help_command.cog is cog:
             help_command.cog = None

discord/ext/commands/cog.py

@@ -98,6 +98,11 @@ class CogMeta(type):
         attrs['__cog_name__'] = kwargs.pop('name', name)
         attrs['__cog_settings__'] = command_attrs = kwargs.pop('command_attrs', {})
 
+        aliases = kwargs.pop('aliases', [])
+        if not isinstance(aliases, list):
+            raise TypeError("Cog aliases must be a list, not a {0}".format(type(aliases)))
+        attrs['aliases'] = aliases
+
         description = kwargs.pop('description', None)
         if description is None:
             description = inspect.cleandoc(attrs.get('__doc__', ''))