diff --git a/resources/js/ext.uls.ime.js b/resources/js/ext.uls.ime.js
index 334893c2..e80ff0d4 100644
--- a/resources/js/ext.uls.ime.js
+++ b/resources/js/ext.uls.ime.js
@@ -31,7 +31,7 @@
 
 	mw.ime.getLanguagesWithIME = function () {
 		var language,
-			ulsLanguages = mw.config.get( 'wgULSLanguages' ),
+			ulsLanguages = mw.config.get( 'wgULSLanguages' ) || {},
 			availableLanguages = {};
 
 		for ( language in $.ime.languages ) {
diff --git a/resources/js/ext.uls.init.js b/resources/js/ext.uls.init.js
index 1318c5af..2dbe1d0a 100644
--- a/resources/js/ext.uls.init.js
+++ b/resources/js/ext.uls.init.js
@@ -140,7 +140,7 @@
 	};
 
 	mw.uls.getAcceptLanguageList = function () {
-		return mw.config.get( 'wgULSAcceptLanguageList' );
+		return mw.config.get( 'wgULSAcceptLanguageList' ) || [];
 	};
 
 	/**
diff --git a/resources/js/ext.uls.mediawiki.js b/resources/js/ext.uls.mediawiki.js
index 3e32e837..3bc0eeaa 100644
--- a/resources/js/ext.uls.mediawiki.js
+++ b/resources/js/ext.uls.mediawiki.js
@@ -21,7 +21,7 @@
 
 	// MediaWiki overrides for ULS defaults
 	$.fn.uls.defaults = $.extend( $.fn.uls.defaults, {
-		languages: mw.config.get( 'wgULSLanguages' ),
+		languages: mw.config.get( 'wgULSLanguages' ) || {},
 		searchAPI: mw.util.wikiScript( 'api' ) + '?action=languagesearch'
 	} );