diff --git a/requirements.txt b/requirements.txt
index ad0346f..e187fda 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -24,7 +24,7 @@ packaging==19.2
 -e git+https://github.com/ut-parla/Parla.py@a5309ddff6b045ac36cf3f8ae0e8a1750b72d50d#egg=parla
 pathspec==0.6.0
 pluggy==0.13.1
-protobuf==3.15.0
+protobuf==3.18.3
 py==1.10.0
 pycodestyle==2.5.0
 pyflakes==2.1.1
diff --git a/requirements_travis.txt b/requirements_travis.txt
index 9944ad4..71fe25c 100644
--- a/requirements_travis.txt
+++ b/requirements_travis.txt
@@ -24,7 +24,7 @@ packaging==19.2
 -e git+https://github.com/ut-parla/Parla.py@a5309ddff6b045ac36cf3f8ae0e8a1750b72d50d#egg=parla
 pathspec==0.6.0
 pluggy==0.13.1
-protobuf==3.15.0
+protobuf==3.18.3
 py==1.10.0
 pycodestyle==2.5.0
 pyflakes==2.1.1