diff --git a/noxfile.py b/noxfile.py
index 1e153efe2..01f511618 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -34,7 +34,7 @@
 
 DEFAULT_PYTHON_VERSION = "3.8"
 
-UNIT_TEST_PYTHON_VERSIONS: List[str] = ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
+UNIT_TEST_PYTHON_VERSIONS: List[str] = ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12", "3.13"]
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
@@ -195,7 +195,7 @@ def install_unittest_dependencies(session, *constraints):
 def unit(session, protobuf_implementation):
     # Install all test dependencies, then install this package in-place.
 
-    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12"):
+    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12", "3.13"):
         session.skip("cpp implementation is not supported in python 3.11+")
 
     constraints_path = str(
@@ -451,7 +451,7 @@ def docfx(session):
 def prerelease_deps(session, protobuf_implementation):
     """Run all tests with prerelease versions of dependencies installed."""
 
-    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12"):
+    if protobuf_implementation == "cpp" and session.python in ("3.11", "3.12", "3.13"):
         session.skip("cpp implementation is not supported in python 3.11+")
 
     # Install all dependencies
diff --git a/testing/constraints-3.13.txt b/testing/constraints-3.13.txt
new file mode 100644
index 000000000..e69de29bb