diff --git a/mkdocs_simple_plugin/plugin.py b/mkdocs_simple_plugin/plugin.py
index ab3915097..723ef768e 100644
--- a/mkdocs_simple_plugin/plugin.py
+++ b/mkdocs_simple_plugin/plugin.py
@@ -192,7 +192,7 @@ class SimplePlugin(BasePlugin):
                     "*.bmp", "*.tif", "*.tiff", "*.gif", "*.svg", "*.jpeg",
                     "*.jpg", "*.jif", "*.jiff", "*.jp2", "*.jpx", "*.j2k",
                     "*.j2c", "*.fpx", "*.pcd", "*.png", "*.pdf", "CNAME",
-                    "*.snippet", ".pages"
+                    "*.snippet", ".pages", ".nav.yml"
                 ])),
         #
         # ### semiliterate
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
new file mode 100644
index 000000000..fa06dcd66
--- /dev/null
+++ b/tests/test_plugin.py
@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+"""Test mkdocs_simple_plugin.plugin."""
+import unittest
+
+from mkdocs_simple_plugin.plugin import SimplePlugin
+
+
+class TestSimplePlugin(unittest.TestCase):
+    """Test SimplePlugin configuration."""
+
+    def test_default_include_preserves_navigation_files(self):
+        """Test default navigation files are copied into generated docs."""
+        plugin = SimplePlugin()
+        plugin.load_config({})
+
+        self.assertIn(".pages", plugin.config["include"])
+        self.assertIn(".nav.yml", plugin.config["include"])
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tests/test_simple.py b/tests/test_simple.py
index b790e3b4b..1c029b74b 100644
--- a/tests/test_simple.py
+++ b/tests/test_simple.py
@@ -145,8 +145,9 @@ def test_is_doc_file(self):
         self.assertTrue(simple_test.is_doc_file(name="helloworld.md"))
         self.assertFalse(simple_test.is_doc_file(name="md.helloworld"))
 
-        simple_test.doc_glob = [".pages"]
+        simple_test.doc_glob = [".pages", ".nav.yml"]
         self.assertTrue(simple_test.is_doc_file(name=".pages"))
+        self.assertTrue(simple_test.is_doc_file(name=".nav.yml"))
 
     def test_get_files(self):
         """Test getting all files."""