diff --git a/raven/i18n.py b/raven/i18n.py
index 75c04be..4778842 100644
--- a/raven/i18n.py
+++ b/raven/i18n.py
@@ -6,7 +6,7 @@ from raven.pluginregistry import PluginRegistry
 from raven.settings.settingsstore import SettingsStore
 
 settings = SettingsStore.load()
-locale = os.environ['LANG'] if os.environ['LANG'] else "en"
+locale = os.environ['LANG'] if 'LANG' in os.environ and os.environ['LANG'] else "en"
 locale = settings.session.get('general', 'lang', fallback=locale)
 
 _ = False