diff --git a/.circleci/config.yml b/.circleci/config.yml
index 01242a41d15b..7e481f97d1dc 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -3,7 +3,7 @@ version: 2
 jobs:
   build:
     docker:
-      - image: googleapis/nox:0.11.2
+      - image: googleapis/nox:0.17.0
     steps:
       - checkout
       - run:
diff --git a/appveyor/requirements.txt b/appveyor/requirements.txt
index 24cc58840e72..45a4e4c25627 100644
--- a/appveyor/requirements.txt
+++ b/appveyor/requirements.txt
@@ -3,4 +3,4 @@
 # pip will build them from source using the MSVC compiler matching the
 # target Python version and architecture
 wheel
-nox-automation==0.11.2
+nox-automation>=0.17.0
diff --git a/bigquery/nox.py b/bigquery/nox.py
index a0211fba9b3d..9851f53d188d 100644
--- a/bigquery/nox.py
+++ b/bigquery/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/bigtable/nox.py b/bigtable/nox.py
index 611de0bc9338..40d997acc88b 100644
--- a/bigtable/nox.py
+++ b/bigtable/nox.py
@@ -48,7 +48,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/datastore/nox.py b/datastore/nox.py
index 5171bf0bb012..983152e7db92 100644
--- a/datastore/nox.py
+++ b/datastore/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
@@ -70,7 +70,7 @@ def doctests(session):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Doctests run against Python 3.6 only.
     # It is difficult to make doctests run against both Python 2 and Python 3
diff --git a/error_reporting/nox.py b/error_reporting/nox.py
index db245cfd74e8..08edc6987ab9 100644
--- a/error_reporting/nox.py
+++ b/error_reporting/nox.py
@@ -78,7 +78,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/language/nox.py b/language/nox.py
index 569bcb925fac..485ee930d7fb 100644
--- a/language/nox.py
+++ b/language/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/logging/nox.py b/logging/nox.py
index 9a9eb10ef3d3..1d9d5f184e43 100644
--- a/logging/nox.py
+++ b/logging/nox.py
@@ -52,7 +52,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/monitoring/nox.py b/monitoring/nox.py
index b4271686aa5a..dcde9c484b0a 100644
--- a/monitoring/nox.py
+++ b/monitoring/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/pubsub/nox.py b/pubsub/nox.py
index acd70b44ce0b..dd7b09330524 100644
--- a/pubsub/nox.py
+++ b/pubsub/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/spanner/nox.py b/spanner/nox.py
index 5c81a7d4c671..7332af05f0e9 100644
--- a/spanner/nox.py
+++ b/spanner/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/speech/nox.py b/speech/nox.py
index 57c0cc4f7e06..bcacf2d59cd6 100644
--- a/speech/nox.py
+++ b/speech/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/storage/nox.py b/storage/nox.py
index 171050be8be1..f50de86bfdfa 100644
--- a/storage/nox.py
+++ b/storage/nox.py
@@ -50,7 +50,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/translate/nox.py b/translate/nox.py
index f59a2825ed9b..3d006f1f0e27 100644
--- a/translate/nox.py
+++ b/translate/nox.py
@@ -49,7 +49,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run the system tests against latest Python 2 and Python 3 only.
     session.interpreter = 'python{}'.format(python_version)
diff --git a/vision/nox.py b/vision/nox.py
index d5d3f3412ef7..8761fa6fccd6 100644
--- a/vision/nox.py
+++ b/vision/nox.py
@@ -46,7 +46,7 @@ def system_tests(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run unit tests against all supported versions of Python.
     session.interpreter = 'python{}'.format(python_version)
@@ -67,7 +67,7 @@ def system_tests_manual_layer(session, python_version):
 
     # Sanity check: Only run system tests if the environment variable is set.
     if not os.environ.get('GOOGLE_APPLICATION_CREDENTIALS', ''):
-        return
+        session.skip('Credentials must be set via environment variable.')
 
     # Run unit tests against all supported versions of Python.
     session.interpreter = 'python{}'.format(python_version)