diff --git a/src/jquery.uls.data.utils.js b/src/jquery.uls.data.utils.js
index ab0b3d6..5646053 100644
--- a/src/jquery.uls.data.utils.js
+++ b/src/jquery.uls.data.utils.js
@@ -220,7 +220,6 @@
 		return $.uls.data.getLanguagesByScriptGroupInRegions( [ region ] );
 	};
 
-
 	/**
 	 * Returns an associative array of all languages,
 	 * grouped by script group.
@@ -237,23 +236,20 @@
 	 */
 	$.uls.data.getLanguagesByScriptGroup = function ( languages ) {
 		var languagesByScriptGroup = {},
-			scriptGroup,
-			language,
-			langScriptGroup;
+			language, codeToAdd, langScriptGroup;
 
-		for ( scriptGroup in $.uls.data.scriptgroups ) {
-			for ( language in languages ) {
-				langScriptGroup = $.uls.data.getScriptGroupOfLanguage( language );
+		for ( language in languages ) {
+			codeToAdd = $.uls.data.isRedirect( language ) || language;
 
-				if ( langScriptGroup !== scriptGroup ) {
-					continue;
-				}
+			langScriptGroup = $.uls.data.getScriptGroupOfLanguage( codeToAdd );
 
-				if ( !languagesByScriptGroup[scriptGroup] ) {
-					languagesByScriptGroup[scriptGroup] = [];
-				}
+			if ( !languagesByScriptGroup[langScriptGroup] ) {
+				languagesByScriptGroup[langScriptGroup] = [];
+			}
 
-				languagesByScriptGroup[scriptGroup].push( language );
+			// Prevent duplicate adding of redirects
+			if ( $.inArray( codeToAdd, languagesByScriptGroup[langScriptGroup] ) === -1 ) {
+				languagesByScriptGroup[langScriptGroup].push( codeToAdd );
 			}
 		}
 
diff --git a/src/jquery.uls.regionfilter.js b/src/jquery.uls.regionfilter.js
index b0c8732..8377a65 100644
--- a/src/jquery.uls.regionfilter.js
+++ b/src/jquery.uls.regionfilter.js
@@ -80,10 +80,17 @@
 				// Get the languages grouped by script group
 				var languagesByScriptGroup = $.uls.data.getLanguagesByScriptGroup( this.options.languages );
 
-				for ( var scriptGroup in languagesByScriptGroup ) {
+				// Make sure that we go by the original order
+				// of script groups
+				for ( var scriptGroup in $.uls.data.scriptgroups ) {
 					// Get the languages for the script group
 					var languages = languagesByScriptGroup[scriptGroup];
 
+					// It's possible that some script groups are missing
+					if ( !languages ) {
+						continue;
+					}
+
 					// Sort it based on autonym
 					languages.sort( $.uls.data.sortByAutonym );
 
diff --git a/test/jquery.uls.test.js b/test/jquery.uls.test.js
index a00fb0e..ab10a5d 100644
--- a/test/jquery.uls.test.js
+++ b/test/jquery.uls.test.js
@@ -89,7 +89,7 @@
 		assert.ok( $.fn.uls, "$.fn.uls is defined" );
 	} );
 
-	test( "-- $.uls.data testing", 45, function ( assert ) {
+	test( "-- $.uls.data testing", 46, function ( assert ) {
 		// Add a language in run time.
 		// This is done early to make sure that it doesn't break other functions.
 		$.uls.data.addLanguage( 'qqq', {
@@ -198,6 +198,24 @@
 		assert.strictEqual( $.uls.data.getAutonym( 'pa' ), 'ਪੰਜਾਬੀ', 'Correct autonym of the Punjabi language was selected using code pa.' );
 		assert.strictEqual( $.uls.data.getAutonym( 'pa-guru' ), 'ਪੰਜਾਬੀ', 'Correct autonym of the Punjabi language was selected using code pa-guru.' );
 
+		var languagesToGroup = {
+				'en': 'English',
+				'fiu-vro': 'Võro', // Alias before target
+				'ru': 'русский',
+				'sr': 'српски', // Alias before target
+				'sr-cyrl': 'српски', // Target before alias
+				'sr-latn': 'srpski', // Target before alias
+				'sr-el': 'srpski', // Alias after target
+				'vro': 'Võro' // Target after alias
+			},
+			groupedLanguages = {
+				Latin: [ 'en', 'vro', 'sr-latn' ],
+				Cyrillic: [ 'ru', 'sr-cyrl' ]
+			};
+
+		assert.deepEqual( $.uls.data.getLanguagesByScriptGroup( languagesToGroup ), groupedLanguages,
+			'A custom list of languages is grouped correctly using getLanguagesByScriptGroup.' );
+
 		var languagesByScriptGroupInEMEA = $.uls.data.getLanguagesByScriptGroupInRegions( $.uls.data.getRegionsInGroup( 3 ) );
 		assert.deepEqual( languagesByScriptGroupInEMEA['WestCaucasian'], [
 			'hy', 'ka', 'xmf'