diff --git a/mkt/webapps/models.py b/mkt/webapps/models.py
index 65ef17d40ca..7940d057de7 100644
--- a/mkt/webapps/models.py
+++ b/mkt/webapps/models.py
@@ -807,10 +807,16 @@ def supported_locales(self):
         for the current public version.
 
         """
+        languages = []
+        for locale in self.current_version.supported_locales.split(','):
+            if locale:
+                language = settings.LANGUAGES.get(locale.lower())
+                if language:
+                    languages.append(language)
+
         return (
-            settings.LANGUAGES[self.default_locale.lower()],
-            sorted([settings.LANGUAGES[l.lower()] for l
-                    in self.current_version.supported_locales.split(',')])
+            settings.LANGUAGES.get(self.default_locale.lower()),
+            sorted(languages)
         )
 
 
diff --git a/mkt/webapps/tests/test_models.py b/mkt/webapps/tests/test_models.py
index e9d9d7df95c..27be9688123 100644
--- a/mkt/webapps/tests/test_models.py
+++ b/mkt/webapps/tests/test_models.py
@@ -434,6 +434,16 @@ def test_supported_locale_property(self):
         eq_(app.supported_locales,
             (u'English (US)', [u'Deutsch', u'Fran\xe7ais']))
 
+    def test_supported_locale_property_empty(self):
+        app = app_factory()
+        eq_(app.supported_locales, (u'English (US)', []))
+
+    def test_supported_locale_property_bad(self):
+        app = app_factory()
+        app.versions.latest().update(supported_locales='de,xx', _signal=False)
+        app.reload()
+        eq_(app.supported_locales, (u'English (US)', [u'Deutsch']))
+
 
 class TestPackagedAppManifestUpdates(amo.tests.TestCase):
     # Note: More extensive tests for `Addon.update_names` are in the Addon