diff --git a/setup.py b/setup.py
index 38f6d0e6e..b779b4ce1 100644
--- a/setup.py
+++ b/setup.py
@@ -37,7 +37,7 @@
     "google-cloud-core >= 1.4.1, <3.0.0dev",
     "proto-plus >= 1.22.0, <2.0.0dev",
     "proto-plus >= 1.22.2, <2.0.0dev; python_version>='3.11'",
-    "protobuf>=3.19.5,<5.0.0dev,!=3.20.0,!=3.20.1,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
+    "protobuf>=3.20.2,<6.0.0dev,!=3.20.0,!=3.20.1,!=4.21.0,!=4.21.1,!=4.21.2,!=4.21.3,!=4.21.4,!=4.21.5",
 ]
 extras = {}