diff --git a/src/drake_extension/__init__.py b/src/drake_extension/__init__.py
index de3e8df..27875d7 100644
--- a/src/drake_extension/__init__.py
+++ b/src/drake_extension/__init__.py
@@ -1,4 +1,5 @@
 from __future__ import annotations
+from pydrake.systems.framework import LeafSystem
 from .drake_extension_ext import __doc__, SimpleAdder
 
-__all__ = ["__doc__", "SimpleAdder"]
+__all__ = ["__doc__", "SimpleAdder", "LeafSystem"]