diff --git a/sphinx_autobuild/__main__.py b/sphinx_autobuild/__main__.py
index b1f058f..c980f92 100644
--- a/sphinx_autobuild/__main__.py
+++ b/sphinx_autobuild/__main__.py
@@ -60,6 +60,7 @@ def main(argv=()):
     watch_dirs = [src_dir] + args.additional_watched_dirs
     ignore_dirs = [
         ".git",
+        ".jj",
         ".hg",
         ".idea",
         ".mypy_cache",