diff --git a/setup.py b/setup.py
index 26b520e..5ee243f 100644
--- a/setup.py
+++ b/setup.py
@@ -35,7 +35,7 @@
     description='Google Authentication Library',
     long_description=long_description,
     url='https://github.com/GoogleCloudPlatform/google-auth-library-python',
-    packages=find_packages(exclude='tests'),
+    packages=find_packages(exclude=('tests', 'system_tests')),
     namespace_packages=('google',),
     install_requires=DEPENDENCIES,
     license='Apache 2.0',