diff --git a/pyproject.toml b/pyproject.toml
index 90ca0989..5226e161 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -22,6 +22,8 @@ classifiers = [
 packages = [
     { include = "dbus_fast", from = "src" },
 ]
+# Make sure we don't package temporary C files generated by the build process
+exclude = [ "**/*.c" ]
 
 [tool.poetry.build]
 generate-setup-file = true