diff --git a/requirements.txt b/requirements.txt
index bf7ac72..6b9648c 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -11,7 +11,7 @@ Markdown==2.6.11
 matplotlib==2.1.1
 mujoco-py==0.5.7
 numpy==1.14.0
-protobuf==3.5.1
+protobuf==3.15.0
 pyglet==1.3.0
 PyOpenGL==3.1.0
 pyparsing==2.2.0