diff --git a/picard/formats/vorbis.py b/picard/formats/vorbis.py
index da3274ba5..ecbedade5 100644
--- a/picard/formats/vorbis.py
+++ b/picard/formats/vorbis.py
@@ -72,7 +72,7 @@ def is_valid_key(key):
     Valid characters for Vorbis comment field names are
     ASCII 0x20 through 0x7D, 0x3D ('=') excluded.
     """
-    return INVALID_CHARS.search(key) is None
+    return key and INVALID_CHARS.search(key) is None
 
 
 def flac_sort_pics_after_tags(metadata_blocks):
diff --git a/test/formats/test_vorbis.py b/test/formats/test_vorbis.py
index 214b9f5b8..400302443 100644
--- a/test/formats/test_vorbis.py
+++ b/test/formats/test_vorbis.py
@@ -67,6 +67,7 @@ VALID_KEYS = [
 ]
 
 INVALID_KEYS = [
+    '',
     'invalid=key',
     'invalid\x19key',
     'invalid~key',
@@ -91,7 +92,7 @@ class CommonVorbisTests:
             supports_tag = self.format.supports_tag
             for key in VALID_KEYS + list(TAGS.keys()):
                 self.assertTrue(supports_tag(key), '%r should be supported' % key)
-            for key in INVALID_KEYS + ['']:
+            for key in INVALID_KEYS:
                 self.assertFalse(supports_tag(key), '%r should be unsupported' % key)
 
         @skipUnlessTestfile