diff --git a/addons/mail/models/mail_thread.py b/addons/mail/models/mail_thread.py
index a733f2f329b..de66fbc50e2 100644
--- a/addons/mail/models/mail_thread.py
+++ b/addons/mail/models/mail_thread.py
@@ -7,7 +7,6 @@ import dateutil
 import email
 import hashlib
 import hmac
-import json
 import lxml
 import logging
 import pytz