diff --git a/.librarian/generator-input/client-post-processing/firestore-integration.yaml b/.librarian/generator-input/client-post-processing/firestore-integration.yaml
index 50defa6a4829..d31022a3b362 100644
--- a/.librarian/generator-input/client-post-processing/firestore-integration.yaml
+++ b/.librarian/generator-input/client-post-processing/firestore-integration.yaml
@@ -647,6 +647,26 @@ replacements:
           "pytest-xdist",
       ]
     count: 1
+  - paths: [
+      packages/google-cloud-firestore/noxfile.py
+    ]
+    before: 'RUFF_VERSION = "ruff==0\.14\.14"\n\nLINT_PATHS ='
+    after: |-
+      RUFF_VERSION = "ruff==0.14.14"
+      # Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+      # before pytest_configure hooks run, turning pytest-asyncio's unset
+      # asyncio_default_fixture_loop_scope warning into an error. Remove once
+      # pytest 9.2+ warning and fixture scope deprecations are resolved.
+      PYTEST_VERSION = "pytest<9.2"
+
+      LINT_PATHS =
+    count: 1
+  - paths: [
+      packages/google-cloud-firestore/noxfile.py
+    ]
+    before: '"pytest",'
+    after: 'PYTEST_VERSION,'
+    count: 2
   - paths: [
       packages/google-cloud-firestore/noxfile.py
     ]
diff --git a/.librarian/generator-input/client-post-processing/integrate-isolated-handwritten-code.yaml b/.librarian/generator-input/client-post-processing/integrate-isolated-handwritten-code.yaml
index c200d3069dbf..1c686e8d7269 100644
--- a/.librarian/generator-input/client-post-processing/integrate-isolated-handwritten-code.yaml
+++ b/.librarian/generator-input/client-post-processing/integrate-isolated-handwritten-code.yaml
@@ -388,6 +388,26 @@ replacements:
     before: '\n        "--check-untyped-defs",'
     after: '\n        # TODO(https://github.com/googleapis/google-cloud-python/issues/16083)\n        # "--check-untyped-defs",'
     count: 1
+  - paths: [
+      "packages/google-cloud-error-reporting/noxfile.py",
+    ]
+    before: 'RUFF_VERSION = "ruff==0\.14\.14"\n\nLINT_PATHS ='
+    after: |-
+      RUFF_VERSION = "ruff==0.14.14"
+      # Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+      # before pytest_configure hooks run, turning pytest-asyncio's unset
+      # asyncio_default_fixture_loop_scope warning into an error. Remove once
+      # pytest 9.2+ warning and fixture scope deprecations are resolved.
+      PYTEST_VERSION = "pytest<9.2"
+
+      LINT_PATHS =
+    count: 1
+  - paths: [
+      "packages/google-cloud-error-reporting/noxfile.py",
+    ]
+    before: '"pytest",'
+    after: 'PYTEST_VERSION,'
+    count: 2
   - paths: [
       "packages/google-cloud-monitoring-dashboards/noxfile.py",
     ]
diff --git a/.librarian/generator-input/client-post-processing/logging-integration.yaml b/.librarian/generator-input/client-post-processing/logging-integration.yaml
index 9db37f582424..f1f2d15c9e9e 100644
--- a/.librarian/generator-input/client-post-processing/logging-integration.yaml
+++ b/.librarian/generator-input/client-post-processing/logging-integration.yaml
@@ -452,6 +452,26 @@ replacements:
           "types",
       )
     count: 1
+  - paths: [
+      packages/google-cloud-logging/noxfile.py
+    ]
+    before: 'RUFF_VERSION = "ruff==0\.14\.14"\n\nLINT_PATHS ='
+    after: |-
+      RUFF_VERSION = "ruff==0.14.14"
+      # Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+      # before pytest_configure hooks run, turning pytest-asyncio's unset
+      # asyncio_default_fixture_loop_scope warning into an error. Remove once
+      # pytest 9.2+ warning and fixture scope deprecations are resolved.
+      PYTEST_VERSION = "pytest<9.2"
+
+      LINT_PATHS =
+    count: 1
+  - paths: [
+      packages/google-cloud-logging/noxfile.py
+    ]
+    before: '"pytest",'
+    after: 'PYTEST_VERSION,'
+    count: 2
   - paths: [
       packages/google-cloud-logging/noxfile.py
     ]
diff --git a/.librarian/generator-input/client-post-processing/pubsub-integration.yaml b/.librarian/generator-input/client-post-processing/pubsub-integration.yaml
index 238f99e447df..6cdee52bb96d 100644
--- a/.librarian/generator-input/client-post-processing/pubsub-integration.yaml
+++ b/.librarian/generator-input/client-post-processing/pubsub-integration.yaml
@@ -501,6 +501,24 @@ replacements:
           """Skipping until Pub/Sub migration is complete."""
           session.skip("Skipping core_deps_from_source for google-cloud-pubsub.")
     count: 1
+  - paths:
+      - "packages/google-cloud-pubsub/noxfile.py"
+    before: 'RUFF_VERSION = "ruff==0\.14\.14"\n\nLINT_PATHS ='
+    after: |-
+      RUFF_VERSION = "ruff==0.14.14"
+      # Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+      # before pytest_configure hooks run, turning pytest-asyncio's unset
+      # asyncio_default_fixture_loop_scope warning into an error. Remove once
+      # pytest 9.2+ warning and fixture scope deprecations are resolved.
+      PYTEST_VERSION = "pytest<9.2"
+
+      LINT_PATHS =
+    count: 1
+  - paths:
+      - "packages/google-cloud-pubsub/noxfile.py"
+    before: '"pytest",'
+    after: 'PYTEST_VERSION,'
+    count: 2
   - paths:
       - "packages/google-cloud-pubsub/noxfile.py"
     before: '"--cov=google",'
diff --git a/packages/db-dtypes/noxfile.py b/packages/db-dtypes/noxfile.py
index 5d0c8b4980a9..fca37e128fea 100644
--- a/packages/db-dtypes/noxfile.py
+++ b/packages/db-dtypes/noxfile.py
@@ -31,6 +31,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
 ISORT_VERSION = "isort==5.11.0"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "db_dtypes", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -48,7 +53,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -61,7 +66,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.12"]
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
@@ -262,7 +267,7 @@ def prerelease(session, tests_path):
     session.install(
         "mock",
         "asyncmock",
-        "pytest",
+        PYTEST_VERSION,
         "pytest-cov",
         "pytest-asyncio",
         # tzdata is only needed for testing: pandas 3.0+ no longer installs
diff --git a/packages/google-api-core/noxfile.py b/packages/google-api-core/noxfile.py
index 4ae56dc0f008..cc934e4b66ca 100644
--- a/packages/google-api-core/noxfile.py
+++ b/packages/google-api-core/noxfile.py
@@ -29,6 +29,11 @@
 import nox
 
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
 ALL_PYTHON = ["3.10", "3.11", "3.12", "3.13", "3.14", "3.15"]
@@ -220,7 +225,7 @@ def default(
         unittest.skip("The pre-release session cannot be run without grpc")
 
     session.install(
-        "pytest",
+        PYTEST_VERSION,
         "pytest-cov",
         "pytest-mock",
         "pytest-xdist",
diff --git a/packages/google-auth-httplib2/noxfile.py b/packages/google-auth-httplib2/noxfile.py
index e0a9b93502a4..68fe2f40313c 100644
--- a/packages/google-auth-httplib2/noxfile.py
+++ b/packages/google-auth-httplib2/noxfile.py
@@ -29,6 +29,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
 ISORT_VERSION = "isort==5.11.0"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "google_auth_httplib2.py", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -44,7 +49,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -60,7 +65,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.10"]
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
diff --git a/packages/google-cloud-core/noxfile.py b/packages/google-cloud-core/noxfile.py
index 772c0c136b3d..2221c42d66f9 100644
--- a/packages/google-cloud-core/noxfile.py
+++ b/packages/google-cloud-core/noxfile.py
@@ -23,6 +23,11 @@
 
 BLACK_VERSION = "black==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning (inherited via shared CI venvs)
+# into an error. Remove once pytest 9.2+ deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 BLACK_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -136,7 +141,7 @@ def default(session):
     )
 
     # Install all test dependencies, then install local packages in-place.
-    session.install("pytest", "pytest-cov", "-c", constraints_path)
+    session.install(PYTEST_VERSION, "pytest-cov", "-c", constraints_path)
     session.install("-e", ".[grpc]", "-c", constraints_path)
 
     # Run py.test against the unit tests.
@@ -275,7 +280,7 @@ def prerelease_deps(session, protobuf_implementation):
     """Run all tests with prerelease versions of dependencies installed."""
 
     # Install all test dependencies, then install local packages in-place.
-    session.install("pytest", "pytest-cov")
+    session.install(PYTEST_VERSION, "pytest-cov")
     session.install("-e", ".[grpc]")
 
     # Because we test minimum dependency versions on the minimum Python
@@ -362,7 +367,7 @@ def core_deps_from_source(session, protobuf_implementation):
     """
 
     # Install all test dependencies, then install local packages in-place.
-    session.install("pytest", "pytest-cov")
+    session.install(PYTEST_VERSION, "pytest-cov")
     session.install("-e", ".[grpc]")
 
     # Because we test minimum dependency versions on the minimum Python
diff --git a/packages/google-cloud-dns/noxfile.py b/packages/google-cloud-dns/noxfile.py
index 0c6507c42a5d..5f659a148194 100644
--- a/packages/google-cloud-dns/noxfile.py
+++ b/packages/google-cloud-dns/noxfile.py
@@ -31,6 +31,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
 ISORT_VERSION = "isort==5.11.0"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -46,7 +51,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -58,7 +63,7 @@
 
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
diff --git a/packages/google-cloud-documentai-toolbox/noxfile.py b/packages/google-cloud-documentai-toolbox/noxfile.py
index e6ac183ea803..c1d2ab53dde8 100644
--- a/packages/google-cloud-documentai-toolbox/noxfile.py
+++ b/packages/google-cloud-documentai-toolbox/noxfile.py
@@ -31,6 +31,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
 ISORT_VERSION = "isort==5.11.0"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -47,7 +52,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -60,7 +65,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.12"]
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
diff --git a/packages/google-cloud-error-reporting/noxfile.py b/packages/google-cloud-error-reporting/noxfile.py
index 4c37e91d4b4e..5cc4d0f63ee5 100644
--- a/packages/google-cloud-error-reporting/noxfile.py
+++ b/packages/google-cloud-error-reporting/noxfile.py
@@ -23,6 +23,11 @@
 import nox
 
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
@@ -66,7 +71,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -79,7 +84,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ALL_PYTHON
 SYSTEM_TEST_STANDARD_DEPENDENCIES = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
diff --git a/packages/google-cloud-firestore/noxfile.py b/packages/google-cloud-firestore/noxfile.py
index b83aa0a5c973..9391ad33853d 100644
--- a/packages/google-cloud-firestore/noxfile.py
+++ b/packages/google-cloud-firestore/noxfile.py
@@ -23,6 +23,11 @@
 import nox
 
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
@@ -66,7 +71,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio==0.21.2",
 ]
@@ -83,7 +88,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ALL_PYTHON
 SYSTEM_TEST_STANDARD_DEPENDENCIES = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
     "pytest-asyncio==0.21.2",
diff --git a/packages/google-cloud-logging/noxfile.py b/packages/google-cloud-logging/noxfile.py
index f8468c73410f..13cc30695b6c 100644
--- a/packages/google-cloud-logging/noxfile.py
+++ b/packages/google-cloud-logging/noxfile.py
@@ -23,6 +23,11 @@
 import nox
 
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
@@ -66,7 +71,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -83,7 +88,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ALL_PYTHON
 SYSTEM_TEST_STANDARD_DEPENDENCIES = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
diff --git a/packages/google-cloud-pubsub/noxfile.py b/packages/google-cloud-pubsub/noxfile.py
index 219dbea9718f..7d3dde3e27d8 100644
--- a/packages/google-cloud-pubsub/noxfile.py
+++ b/packages/google-cloud-pubsub/noxfile.py
@@ -23,6 +23,11 @@
 import nox
 
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
@@ -66,7 +71,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -81,7 +86,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ALL_PYTHON
 SYSTEM_TEST_STANDARD_DEPENDENCIES = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = [
diff --git a/packages/google-cloud-runtimeconfig/noxfile.py b/packages/google-cloud-runtimeconfig/noxfile.py
index c8ddaaa120ef..b34f7bf306b5 100644
--- a/packages/google-cloud-runtimeconfig/noxfile.py
+++ b/packages/google-cloud-runtimeconfig/noxfile.py
@@ -31,6 +31,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
 ISORT_VERSION = "isort==5.11.0"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning into an error. Remove once
+# pytest 9.2+ warning and fixture scope deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 LINT_PATHS = ["docs", "google", "tests", "noxfile.py", "setup.py"]
 
 DEFAULT_PYTHON_VERSION = "3.14"
@@ -46,7 +51,7 @@
 UNIT_TEST_STANDARD_DEPENDENCIES = [
     "mock",
     "asyncmock",
-    "pytest",
+    PYTEST_VERSION,
     "pytest-cov",
     "pytest-asyncio",
 ]
@@ -59,7 +64,7 @@
 SYSTEM_TEST_PYTHON_VERSIONS: List[str] = ["3.12"]
 SYSTEM_TEST_STANDARD_DEPENDENCIES: List[str] = [
     "mock",
-    "pytest",
+    PYTEST_VERSION,
     "google-cloud-testutils",
 ]
 SYSTEM_TEST_EXTERNAL_DEPENDENCIES: List[str] = []
diff --git a/packages/google-cloud-testutils/noxfile.py b/packages/google-cloud-testutils/noxfile.py
index 5a5809c9d760..4b07c13bbeb2 100644
--- a/packages/google-cloud-testutils/noxfile.py
+++ b/packages/google-cloud-testutils/noxfile.py
@@ -16,6 +16,7 @@
 
 
 from __future__ import absolute_import
+
 import os
 import pathlib
 import re
@@ -37,6 +38,11 @@
 DEFAULT_PYTHON_VERSION = "3.14"
 BLACK_VERSION = "black==23.7.0"
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning (inherited via shared CI venvs)
+# into an error. Remove once pytest 9.2+ deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 BLACK_PATHS = ["test_utils", "setup.py"]
 CURRENT_DIRECTORY = pathlib.Path(__file__).parent.absolute()
 # Path to the centralized mypy configuration file at the repository root.
@@ -154,7 +160,7 @@ def unit(session):
         "-e", "tests/unit/resources/good_package", "tests/unit/resources/bad_package"
     )
 
-    session.install("pytest", "pytest-cov")
+    session.install(PYTEST_VERSION, "pytest-cov")
     session.install("-e", ".", "-c", constraints_path)
 
     # Run py.test against the unit tests.
@@ -303,7 +309,7 @@ def prerelease_deps(session):
         "-e", "tests/unit/resources/good_package", "tests/unit/resources/bad_package"
     )
 
-    session.install("pytest", "pytest-cov")
+    session.install(PYTEST_VERSION, "pytest-cov")
     session.install("-e", ".", "-c", constraints_path)
 
     # Because we test minimum dependency versions on the minimum Python
@@ -371,7 +377,7 @@ def core_deps_from_source(session):
         "-e", "tests/unit/resources/good_package", "tests/unit/resources/bad_package"
     )
 
-    session.install("pytest", "pytest-cov")
+    session.install(PYTEST_VERSION, "pytest-cov")
     session.install("-e", ".", "-c", constraints_path)
 
     # Because we test minimum dependency versions on the minimum Python
diff --git a/packages/proto-plus/noxfile.py b/packages/proto-plus/noxfile.py
index fbdee3b362e0..4b4ba40a7e10 100644
--- a/packages/proto-plus/noxfile.py
+++ b/packages/proto-plus/noxfile.py
@@ -23,6 +23,11 @@
 BLACK_VERSION = "black[jupyter]==23.7.0"
 ISORT_VERSION = "isort==5.11.0"
 RUFF_VERSION = "ruff==0.14.14"
+# Temporarily pin pytest<9.2 because pytest 9.2.0 applies filterwarnings=error
+# before pytest_configure hooks run, turning pytest-asyncio's unset
+# asyncio_default_fixture_loop_scope warning (inherited via shared CI venvs)
+# into an error. Remove once pytest 9.2+ deprecations are resolved.
+PYTEST_VERSION = "pytest<9.2"
 
 LINT_PATHS = ["docs", "proto", "tests", "noxfile.py", "setup.py"]
 
@@ -64,7 +69,7 @@ def unit(session, implementation):
     )
 
     session.env["PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION"] = implementation
-    session.install("coverage", "pytest", "pytest-cov", "pytz")
+    session.install("coverage", PYTEST_VERSION, "pytest-cov", "pytz")
     session.install("-e", ".[testing]", "-c", constraints_path)
 
     # TODO(https://github.com/googleapis/proto-plus-python/issues/403): re-enable `-W=error`
@@ -100,7 +105,7 @@ def prerelease_deps(session, implementation):
     session.env["PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION"] = implementation
 
     # Install test environment dependencies
-    session.install("coverage", "pytest", "pytest-cov", "pytz")
+    session.install("coverage", PYTEST_VERSION, "pytest-cov", "pytz")
 
     # Install the package without dependencies
     session.install("-e", ".", "--no-deps")
@@ -157,7 +162,7 @@ def core_deps_from_source(session, implementation):
     session.env["PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION"] = implementation
 
     # Install test environment dependencies
-    session.install("coverage", "pytest", "pytest-cov", "pytz")
+    session.install("coverage", PYTEST_VERSION, "pytest-cov", "pytz")
 
     # Install the package without dependencies
     session.install("-e", ".", "--no-deps")