diff --git a/src/recommendationservice/requirements.txt b/src/recommendationservice/requirements.txt
index a4ec1a2..554b405 100644
--- a/src/recommendationservice/requirements.txt
+++ b/src/recommendationservice/requirements.txt
@@ -20,7 +20,7 @@ google-python-cloud-debugger==2.9  # via -r requirements.in
 googleapis-common-protos==1.5.6  # via google-api-core
 grpcio-health-checking==1.13.0  # via -r requirements.in
 grpcio==1.16.1            # via -r requirements.in, google-api-core, grpcio-health-checking
-httplib2==0.12.0          # via google-api-python-client, google-auth-httplib2
+httplib2==0.18.0          # via google-api-python-client, google-auth-httplib2
 idna==2.8                 # via requests
 opencensus[stackdriver]==0.1.10  # via -r requirements.in
 protobuf==3.6.1           # via google-api-core, google-cloud-profiler, googleapis-common-protos, grpcio-health-checking