diff --git a/src/somd2/config/_config.py b/src/somd2/config/_config.py
index 37385ec..eeccc4c 100644
--- a/src/somd2/config/_config.py
+++ b/src/somd2/config/_config.py
@@ -1455,7 +1455,7 @@ def _create_parser(cls):
         )
 
         # Add the parameters.
-        for param in params:
+        for param in sorted(params):
             # Convert underscores to hyphens for the command line.
             cli_param = param.replace("_", "-")