diff --git a/docs/conf.py b/docs/conf.py
index fa13c3bd..8ce06ebb 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -54,7 +54,6 @@ MOCK_MODULES = [
     'pykka.future',
     'pykka.registry',
     'pylast',
-    'serial',
     'ws4py',
     'ws4py.messaging',
     'ws4py.server',