diff --git a/pyproject.toml b/pyproject.toml
index d0cefd8..251a228 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -94,7 +94,7 @@ build.hooks.vcs.version-file = "src/filelock/version.py"
 build.targets.sdist.include = [
   "/src",
   "/tests",
-  "/tox.ini",
+  "/tox.toml",
 ]
 version.source = "vcs"