diff --git a/pyproject.toml b/pyproject.toml
index fb4a68cc..37c745b2 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -41,3 +41,8 @@ stage2 = "stage2:main"
 
 [project.gui-scripts]
 mtk_gui = "mtk_gui:main"
+
+[tool.setuptools]
+# See also the MANIFEST.in file.
+# We want to install all the files in the package directories...
+include-package-data = true
\ No newline at end of file