diff --git a/wetb/prepost/misc.py b/wetb/prepost/misc.py
index 73aca12551262ff28b8124ab3f3d6deb5f8a3032..7deb74f99f6cb227a3f517ae25f366a38c596548 100644
--- a/wetb/prepost/misc.py
+++ b/wetb/prepost/misc.py
@@ -726,7 +726,7 @@ def read_excel_files(proot, fext='xlsx', pignore=None, sheet=0,
     df_list = {}
     # find all dlc defintions in the subfolders
     for root, dirs, files in os.walk(proot):
-        for file_name in files:
+        for file_name in sorted(files):
             if not file_name.split('.')[-1] == fext:
                 continue
             f_target = os.path.join(root, file_name)