diff --git a/storage/cloud.py b/storage/cloud.py
index 9148819dd..81c602471 100644
--- a/storage/cloud.py
+++ b/storage/cloud.py
@@ -402,6 +402,9 @@ class S3Storage(_CloudStorage):
     }
     connect_kwargs = {}
     if host:
+      if host.startswith('http:') or host.startswith('https:'):
+        raise ValueError('host name must not start with http:// or https://')
+
       connect_kwargs['host'] = host
     super(S3Storage, self).__init__(boto.s3.connection.S3Connection, boto.s3.key.Key,
                                     connect_kwargs, upload_params, storage_path, s3_access_key,