diff --git a/test_requirements.txt b/test_requirements.txt
index eddd838f..39db479c 100644
--- a/test_requirements.txt
+++ b/test_requirements.txt
@@ -1,6 +1,6 @@
 # Requirements to run unit tests. Tests import from
 # generated code.
-protobuf==5.28.2
+protobuf==5.28.3
 pytest==8.3.3
 pytest-asyncio==0.24.0
 grpc-stubs==1.53.0.5