diff --git a/mailman_sync.py b/mailman_sync.py
index cd2533a..d1db2c5 100755
--- a/mailman_sync.py
+++ b/mailman_sync.py
@@ -13,7 +13,7 @@ import tempfile
 import requests
 
 
-def config_list(mailman_bin: Path, mailing_list: str):
+def config_list(mailman_bin: Path, mailing_list: str, dry_run: bool):
     config_changes = """
 # TODO: set real_name, moderator, subject prefix, and reply-to address
 from_is_list = 1
@@ -38,13 +38,18 @@ forward_auto_discards = 0  # don't notify admin about discards
     with tempfile.NamedTemporaryFile("w", suffix=".py") as config_file:
         config_file.write(config_changes)
         config_file.flush()
+
+        command = [
+            mailman_bin / "config_list",
+            "--inputfile",
+            config_file.name,
+            mailing_list,
+        ]
+        if dry_run:
+            command.append("--checkonly")
+
         output = subprocess.run(
-            [
-                mailman_bin / "config_list",
-                "--inputfile",
-                config_file.name,
-                mailing_list,
-            ],
+            command,
             encoding="ascii",
             capture_output=True,
             check=True,
@@ -97,7 +102,7 @@ def main(mailman_bin: Path, api: str, api_auth: str, list_suffix: str, dry_run:
         list_name = name + list_suffix
         if list_name in existing_lists:
             print(f"Configuring/syncing {list_name}...")
-            config_list(mailman_bin, list_name)
+            config_list(mailman_bin, list_name, dry_run)
             sync_members(mailman_bin, list_name, members, dry_run)
         else:
             print(f"Skipping {list_name}, as it does not exist in Mailman")