diff --git a/chatmastermind/chat.py b/chatmastermind/chat.py
index 759467d..11f1d74 100644
--- a/chatmastermind/chat.py
+++ b/chatmastermind/chat.py
@@ -45,7 +45,7 @@ def read_dir(dir_path: pathlib.Path,
     messages: list[Message] = []
     file_iter = dir_path.glob(glob) if glob else dir_path.iterdir()
     for file_path in sorted(file_iter):
-        if file_path.is_file():
+        if file_path.is_file() and file_path.suffix in Message.file_suffixes:
             try:
                 message = Message.from_file(file_path, mfilter)
                 if message: