diff --git a/pyproject.toml b/pyproject.toml
index 36933cc03..0de5b02e1 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -23,8 +23,8 @@ classifiers = [
 dynamic = [ "version" ]
 urls = { Homepage = "https://github.com/openforcefield/openff-toolkit" }
 
-[tool.setuptools.packages]
-find = {}
+[tool.setuptools.packages.find]
+include = [ 'openff.toolkit*' ]
 
 [tool.ruff]
 line-length = 119