diff --git a/requirements.txt b/requirements.txt
index d85ff9d..8fa5b1a 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -72,7 +72,7 @@ ply==3.8
 proto-google-cloud-datastore-v1==0.90.4
 proto-google-cloud-error-reporting-v1beta1==0.15.3
 proto-google-cloud-logging-v2==0.91.3
-protobuf==3.5.2.post1
+protobuf==3.18.3
 psutil==5.4.5
 py==1.5.3
 pyasn1==0.4.2
@@ -171,7 +171,7 @@ ply==3.8
 proto-google-cloud-datastore-v1==0.90.4
 proto-google-cloud-error-reporting-v1beta1==0.15.3
 proto-google-cloud-logging-v2==0.91.3
-protobuf==3.5.2.post1
+protobuf==3.18.3
 psutil==5.4.5
 py==1.5.3
 pyasn1==0.4.2
@@ -276,7 +276,7 @@ ply==3.8
 proto-google-cloud-datastore-v1==0.90.4
 proto-google-cloud-error-reporting-v1beta1==0.15.3
 proto-google-cloud-logging-v2==0.91.3
-protobuf==3.5.2.post1
+protobuf==3.18.3
 psutil==5.4.5
 py==1.5.3
 pyasn1==0.4.2