diff --git a/packages/google-cloud-resource-manager/setup.py b/packages/google-cloud-resource-manager/setup.py
index 92359f76ed39..2838495c3c02 100644
--- a/packages/google-cloud-resource-manager/setup.py
+++ b/packages/google-cloud-resource-manager/setup.py
@@ -28,8 +28,9 @@
     # Until this issue is closed
     # https://github.com/googleapis/google-cloud-python/issues/10566
     "google-api-core[grpc] >= 1.31.5, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.0",
-    "proto-plus >= 1.15.0",
-    "grpc-google-iam-v1 >= 0.12.3, <1.0.0dev",
+    "proto-plus >= 1.15.0, <2.0.0dev",
+    "protobuf >= 3.19.0, <4.0.0dev",
+    "grpc-google-iam-v1 >=0.12.4, <1.0.0dev",
 ]
 
 extras = {"libcst": "libcst >= 0.2.5"}
diff --git a/packages/google-cloud-resource-manager/testing/constraints-3.6.txt b/packages/google-cloud-resource-manager/testing/constraints-3.6.txt
index ca8aeffc5857..60b7a7a56ec6 100644
--- a/packages/google-cloud-resource-manager/testing/constraints-3.6.txt
+++ b/packages/google-cloud-resource-manager/testing/constraints-3.6.txt
@@ -8,3 +8,4 @@
 google-api-core==1.31.5
 proto-plus==1.15.0
 grpc-google-iam-v1==0.12.4
+protobuf==3.19.0