diff --git a/geeksbot_web/users/serializers.py b/geeksbot_web/users/serializers.py
index 1cdfd0d..07d20aa 100644
--- a/geeksbot_web/users/serializers.py
+++ b/geeksbot_web/users/serializers.py
@@ -46,7 +46,12 @@ class UserSerializer(serializers.HyperlinkedModelSerializer):
             prev_discrims.add(instance.discriminator)
             validated_data['previous_discriminators'] = list(prev_discrims)
         if 'guilds' in validated_data:
-            instance.guilds.add(*validated_data.pop('guilds'))
+            for guild in validated_data['guilds']:
+                if guild.startswith('-'):
+                    guild = guild[1:]
+                    instance.guilds.remove(guild)
+                else:
+                    instance.guilds.add(guild)
         return super(UserSerializer, self).update(instance, validated_data)