diff --git a/setup.py b/setup.py
index a1f8377..79a7c7d 100644
--- a/setup.py
+++ b/setup.py
@@ -47,8 +47,8 @@
     include_package_data=True,
     install_requires=(
         "google-api-core[grpc] >= 1.32.0, <3.0.0dev,!=2.0.*,!=2.1.*,!=2.2.*,!=2.3.*,!=2.4.*,!=2.5.*,!=2.6.*,!=2.7.*",
-        "proto-plus >= 1.15.0, <2.0.0dev",
-        "protobuf >= 3.19.0, <4.0.0dev",
+        "proto-plus >= 1.22.0, <2.0.0dev",
+        "protobuf >= 3.19.0, <5.0.0dev",
         "grpc-google-iam-v1 >= 0.12.4, <1.0.0dev",
     ),
     python_requires=">=3.7",
diff --git a/testing/constraints-3.7.txt b/testing/constraints-3.7.txt
index f9ec620..75306b3 100644
--- a/testing/constraints-3.7.txt
+++ b/testing/constraints-3.7.txt
@@ -6,6 +6,6 @@
 # e.g., if setup.py has "foo >= 1.14.0, < 2.0.0dev",
 # Then this file should have foo==1.14.0
 google-api-core==1.32.0
-proto-plus==1.15.0
+proto-plus==1.22.0
 grpc-google-iam-v1==0.12.4
 protobuf==3.19.0