diff --git a/slacker/__init__.py b/slacker/__init__.py
index <HASH>..<HASH> 100644
--- a/slacker/__init__.py
+++ b/slacker/__init__.py
@@ -114,13 +114,15 @@ class Groups(BaseAPI):
         return self.get('groups.list',
                         params={'exclude_archived': exclude_archived})
 
-    def history(self, channel, latest=None, oldest=None, count=None):
+    def history(self, channel, latest=None, oldest=None, count=None,
+                inclusive=None):
         return self.get('groups.history',
                         params={
                             'channel': channel,
                             'latest': latest,
                             'oldest': oldest,
-                            'count': count
+                            'count': count,
+                            'inclusive': inclusive
                         })
 
     def invite(self, channel, user):
"inclusive" argument for groups.history API.