diff --git a/requirements.txt b/requirements.txt
index 221a6e73..a8f48a64 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -14,7 +14,7 @@ google-resumable-media==0.3.1
 googleapis-common-protos==1.5.3
 httplib2==0.11.3
 idna==2.7
-protobuf==3.6.1
+protobuf==3.18.3
 pyasn1==0.4.4
 pyasn1-modules==0.2.2
 pytz==2018.5