diff --git a/letsencrypt/client/cli.py b/letsencrypt/client/cli.py
index d3465469e..600d6791b 100644
--- a/letsencrypt/client/cli.py
+++ b/letsencrypt/client/cli.py
@@ -216,7 +216,8 @@ def create_parser():
     parser = configargparse.ArgParser(
         description=__doc__,
         formatter_class=argparse.ArgumentDefaultsHelpFormatter,
-        args_for_setting_config_path=["-c", "--config"])
+        args_for_setting_config_path=["-c", "--config"],
+        default_config_files=constants.DEFAULT_CONFIG_FILES)
 
     # --help is automatically provided by argparse
     parser.add_argument(
diff --git a/letsencrypt/client/constants.py b/letsencrypt/client/constants.py
index 727404030..5c13ea1a3 100644
--- a/letsencrypt/client/constants.py
+++ b/letsencrypt/client/constants.py
@@ -10,6 +10,7 @@ SETUPTOOLS_PLUGINS_ENTRY_POINT = "letsencrypt.plugins"
 
 
 # CLI/IConfig defaults
+DEFAULT_CONFIG_FILES = ["/etc/letsencrypt/cli.ini"]
 DEFAULT_VERBOSE_COUNT = -(logging.WARNING / 10)
 DEFAULT_SERVER = "letsencrypt-demo.org:443"
 DEFAULT_RSA_KEY_SIZE = 2048