diff --git a/requirements.txt b/requirements.txt
index 844de03..2694c1e 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -6,7 +6,7 @@ google-api-python-client==1.7.8
 google-auth==1.6.3
 google-auth-httplib2==0.0.3
 google-auth-oauthlib==0.3.0
-httplib2==0.12.1
+httplib2==0.18.0
 idna==2.8
 jdcal==1.4
 oauthlib==3.0.1