diff --git a/pyproject.toml b/pyproject.toml
index 7a2e796..9b410aa 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -55,7 +55,7 @@ requires = ["setuptools"]
 build-backend = "setuptools.build_meta"
 
 [tool.setuptools]
-packages = ["daphne"]
+package-dir = { daphne = "daphne", twisted = "daphne/twisted" }
 
 [tool.setuptools.dynamic]
 version = { attr = "daphne.__version__" }