diff --git a/setup.py b/setup.py
index a9adf78..f1ec7f6 100644
--- a/setup.py
+++ b/setup.py
@@ -26,7 +26,7 @@
 dependencies = [
     "google-api-core[grpc] >= 2.8.0, <3.0.0dev",
     "proto-plus >= 1.15.0, <2.0.0dev",
-    "protobuf >= 3.19.0, <4.0.0dev",
+    "protobuf >= 3.19.0, <5.0.0dev",
 ]
 url = "https://github.com/googleapis/python-gke-backup"