diff --git a/sphinxext/rediraffe.py b/sphinxext/rediraffe.py
index e43227d..51fb7d8 100644
--- a/sphinxext/rediraffe.py
+++ b/sphinxext/rediraffe.py
@@ -211,10 +211,9 @@ def build_redirects(app: Sphinx, exception: Union[Exception, None]) -> None:
         redirect_to = src_redirect_to.with_suffix("")
 
         if type(app.builder) == DirectoryHTMLBuilder:
-            master_doc = Path(app.config.master_doc).with_suffix("")
-            if redirect_from != master_doc:
+            if redirect_from.name != "index":
                 redirect_from = redirect_from / "index"
-            if redirect_to != master_doc:
+            if redirect_to.name != "index":
                 redirect_to = redirect_to / "index"
 
         redirect_from = redirect_from.with_suffix(".html")
diff --git a/tests/roots/ext/test-dirhtml_user_index_files/conf.py b/tests/roots/ext/test-dirhtml_user_index_files/conf.py
new file mode 100644
index 0000000..8136c0e
--- /dev/null
+++ b/tests/roots/ext/test-dirhtml_user_index_files/conf.py
@@ -0,0 +1,8 @@
+extensions = ["sphinxext.rediraffe"]
+
+master_doc = "index"
+exclude_patterns = ["_build"]
+
+html_theme = "basic"
+
+rediraffe_redirects = "redirects.txt"
diff --git a/tests/roots/ext/test-dirhtml_user_index_files/index.rst b/tests/roots/ext/test-dirhtml_user_index_files/index.rst
new file mode 100644
index 0000000..e5616f3
--- /dev/null
+++ b/tests/roots/ext/test-dirhtml_user_index_files/index.rst
@@ -0,0 +1 @@
+Index File
\ No newline at end of file
diff --git a/tests/roots/ext/test-dirhtml_user_index_files/mydir/index.rst b/tests/roots/ext/test-dirhtml_user_index_files/mydir/index.rst
new file mode 100644
index 0000000..f3736ef
--- /dev/null
+++ b/tests/roots/ext/test-dirhtml_user_index_files/mydir/index.rst
@@ -0,0 +1 @@
+qq
\ No newline at end of file
diff --git a/tests/roots/ext/test-dirhtml_user_index_files/redirects.txt b/tests/roots/ext/test-dirhtml_user_index_files/redirects.txt
new file mode 100644
index 0000000..2543c50
--- /dev/null
+++ b/tests/roots/ext/test-dirhtml_user_index_files/redirects.txt
@@ -0,0 +1 @@
+another.rst mydir/index.rst
\ No newline at end of file
diff --git a/tests/test_ext.py b/tests/test_ext.py
index 2640d95..08909dc 100644
--- a/tests/test_ext.py
+++ b/tests/test_ext.py
@@ -274,6 +274,12 @@ def test_simple(self, app: Sphinx, ensure_redirect):
         assert app.statuscode == 0
         ensure_redirect("another/index.html", "index.html")
 
+    @pytest.mark.sphinx("dirhtml", testroot="dirhtml_user_index_files")
+    def test_index_file_foldering(self, app: Sphinx, ensure_redirect):
+        app.build()
+        assert app.statuscode == 0
+        ensure_redirect("another/index.html", "mydir/index.html")
+
     @pytest.mark.sphinx("dirhtml", testroot="simple", freshenv=False)
     def test_simple_rebuild(self, app_params, make_app, ensure_redirect):
         args, kwargs = app_params