diff --git a/setup.py b/setup.py
index 07e016e..9ed398b 100644
--- a/setup.py
+++ b/setup.py
@@ -96,6 +96,7 @@
         libraries.append("iconv")
 
 # Extensions
+sources.sort()
 extensions = [Extension("pyreadstat.pyreadstat",
                     sources=["pyreadstat/pyreadstat" + ext] + sources,
                     # this dot here is important for cython to find the pxd files