diff --git a/bookmarks/services/auto_tagging.py b/bookmarks/services/auto_tagging.py
index 2608761..840745a 100644
--- a/bookmarks/services/auto_tagging.py
+++ b/bookmarks/services/auto_tagging.py
@@ -7,6 +7,9 @@ def get_tags(script: str, url: str):
     parsed_url = urlparse(url.lower())
     result = set()
 
+    if not parsed_url.hostname:
+        return result
+
     for line in script.lower().split("\n"):
         if "#" in line:
             i = line.index("#")
diff --git a/bookmarks/tests/test_auto_tagging.py b/bookmarks/tests/test_auto_tagging.py
index 320003f..b4213a1 100644
--- a/bookmarks/tests/test_auto_tagging.py
+++ b/bookmarks/tests/test_auto_tagging.py
@@ -14,6 +14,20 @@ class AutoTaggingTestCase(TestCase):
 
         self.assertEqual(tags, {"example"})
 
+    def test_auto_tag_by_domain_handles_invalid_urls(self):
+        script = """
+            example.com example
+            test.com test
+        """
+
+        url = "https://"
+        tags = auto_tagging.get_tags(script, url)
+        self.assertEqual(tags, set([]))
+
+        url = "example.com"
+        tags = auto_tagging.get_tags(script, url)
+        self.assertEqual(tags, set([]))
+
     def test_auto_tag_by_domain_works_with_port(self):
         script = """
             example.com example