diff --git a/lib/private/Server.php b/lib/private/Server.php
index d68a361955..48ee4b27d3 100644
--- a/lib/private/Server.php
+++ b/lib/private/Server.php
@@ -261,7 +261,8 @@ class Server extends ServerContainer implements IServerContainer {
 			return new \OC\L10N\Factory(
 				$c->getConfig(),
 				$c->getRequest(),
-				$c->getUserSession()
+				$c->getUserSession(),
+				\OC::$SERVERROOT
 			);
 		});
 		$this->registerService('URLGenerator', function (Server $c) {
diff --git a/lib/private/l10n/factory.php b/lib/private/l10n/factory.php
index 1440e9510c..fd093c3601 100644
--- a/lib/private/l10n/factory.php
+++ b/lib/private/l10n/factory.php
@@ -64,17 +64,23 @@ class Factory implements IFactory {
 	/** @var IUserSession */
 	protected $userSession;
 
+	/** @var string */
+	protected $serverRoot;
+
 	/**
 	 * @param IConfig $config
 	 * @param IRequest $request
 	 * @param IUserSession $userSession
+	 * @param string $serverRoot
 	 */
 	public function __construct(IConfig $config,
 								IRequest $request,
-								IUserSession $userSession) {
+								IUserSession $userSession,
+								$serverRoot) {
 		$this->config = $config;
 		$this->request = $request;
 		$this->userSession = $userSession;
+		$this->serverRoot = $serverRoot;
 	}
 
 	/**
@@ -186,6 +192,23 @@ class Factory implements IFactory {
 			}
 		}
 
+		// merge with translations from theme
+		$theme = $this->config->getSystemValue('theme');
+		if (!empty($theme)) {
+			$themeDir = $this->serverRoot . '/themes/' . $theme . substr($dir, strlen($this->serverRoot));
+
+			if (is_dir($themeDir)) {
+				$files = scandir($themeDir);
+				if ($files !== false) {
+					foreach ($files as $file) {
+						if (substr($file, -5) === '.json' && substr($file, 0, 4) !== 'l10n') {
+							$available[] = substr($file, 0, -5);
+						}
+					}
+				}
+			}
+		}
+
 		$this->availableLanguages[$key] = $available;
 		return $available;
 	}
@@ -263,22 +286,22 @@ class Factory implements IFactory {
 		$i18nDir = $this->findL10nDir($app);
 		$transFile = strip_tags($i18nDir) . strip_tags($lang) . '.json';
 
-		if ((\OC_Helper::isSubDirectory($transFile, \OC::$SERVERROOT . '/core/l10n/')
-				|| \OC_Helper::isSubDirectory($transFile, \OC::$SERVERROOT . '/lib/l10n/')
-				|| \OC_Helper::isSubDirectory($transFile, \OC::$SERVERROOT . '/settings/l10n/')
+		if ((\OC_Helper::isSubDirectory($transFile, $this->serverRoot . '/core/l10n/')
+				|| \OC_Helper::isSubDirectory($transFile, $this->serverRoot . '/lib/l10n/')
+				|| \OC_Helper::isSubDirectory($transFile, $this->serverRoot . '/settings/l10n/')
 				|| \OC_Helper::isSubDirectory($transFile, \OC_App::getAppPath($app) . '/l10n/')
 			)
 			&& file_exists($transFile)) {
 			// load the translations file
 			$languageFiles[] = $transFile;
+		}
 
-			// merge with translations from theme
-			$theme = $this->config->getSystemValue('theme');
-			if (!empty($theme)) {
-				$transFile = \OC::$SERVERROOT . '/themes/' . $theme . substr($transFile, strlen(\OC::$SERVERROOT));
-				if (file_exists($transFile)) {
-					$languageFiles[] = $transFile;
-				}
+		// merge with translations from theme
+		$theme = $this->config->getSystemValue('theme');
+		if (!empty($theme)) {
+			$transFile = $this->serverRoot . '/themes/' . $theme . substr($transFile, strlen($this->serverRoot));
+			if (file_exists($transFile)) {
+				$languageFiles[] = $transFile;
 			}
 		}
 
@@ -293,14 +316,14 @@ class Factory implements IFactory {
 	 */
 	protected function findL10nDir($app = null) {
 		if (in_array($app, ['core', 'lib', 'settings'])) {
-			if (file_exists(\OC::$SERVERROOT . '/' . $app . '/l10n/')) {
-				return \OC::$SERVERROOT . '/' . $app . '/l10n/';
+			if (file_exists($this->serverRoot . '/' . $app . '/l10n/')) {
+				return $this->serverRoot . '/' . $app . '/l10n/';
 			}
 		} else if ($app && \OC_App::getAppPath($app) !== false) {
 			// Check if the app is in the app folder
 			return \OC_App::getAppPath($app) . '/l10n/';
 		}
-		return \OC::$SERVERROOT . '/core/l10n/';
+		return $this->serverRoot . '/core/l10n/';
 	}
 
 
diff --git a/tests/data/themes/abc/apps/files/l10n/zz.json b/tests/data/themes/abc/apps/files/l10n/zz.json
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/tests/lib/l10n/factorytest.php b/tests/lib/l10n/factorytest.php
index 9f5954d0ee..e4c0eab2e6 100644
--- a/tests/lib/l10n/factorytest.php
+++ b/tests/lib/l10n/factorytest.php
@@ -28,6 +28,9 @@ class FactoryTest extends TestCase {
 	/** @var \OCP\IUserSession|\PHPUnit_Framework_MockObject_MockObject */
 	protected $userSession;
 
+	/** @var string */
+	protected $serverRoot;
+
 	public function setUp() {
 		parent::setUp();
 
@@ -42,6 +45,8 @@ class FactoryTest extends TestCase {
 			->getMock();
 
 		$this->userSession = $this->getMock('\OCP\IUserSession');
+
+		$this->serverRoot = \OC::$SERVERROOT;
 	}
 
 	/**
@@ -54,12 +59,13 @@ class FactoryTest extends TestCase {
 				->setConstructorArgs([
 					$this->config,
 					$this->request,
-					$this->userSession
+					$this->userSession,
+					$this->serverRoot,
 				])
 				->setMethods($methods)
 				->getMock();
 		} else {
-			return new Factory($this->config, $this->request, $this->userSession);
+			return new Factory($this->config, $this->request, $this->userSession, $this->serverRoot);
 		}
 	}
 
@@ -287,6 +293,24 @@ class FactoryTest extends TestCase {
 		];
 	}
 
+	public function testFindAvailableLanguagesWithThemes() {
+		$this->serverRoot .= '/tests/data';
+		$app = 'files';
+
+		$factory = $this->getFactory(['findL10nDir']);
+		$factory->expects($this->once())
+			->method('findL10nDir')
+			->with($app)
+			->willReturn($this->serverRoot . '/apps/files/l10n/');
+		$this->config
+			->expects($this->once())
+			->method('getSystemValue')
+			->with('theme')
+			->willReturn('abc');
+
+		$this->assertEquals(['en', 'zz'], $factory->findAvailableLanguages($app), '', 0.0, 10, true);
+	}
+
 	/**
 	 * @dataProvider dataLanguageExists
 	 *
diff --git a/tests/lib/l10n/l10nlegacytest.php b/tests/lib/l10n/l10nlegacytest.php
index 025f761fe5..1df22ba36b 100644
--- a/tests/lib/l10n/l10nlegacytest.php
+++ b/tests/lib/l10n/l10nlegacytest.php
@@ -124,7 +124,7 @@ class L10nLegacyTest extends \Test\TestCase {
 	}
 
 	public function testFactoryGetLanguageCode() {
-		$factory = new \OC\L10N\Factory($this->getMock('OCP\IConfig'), $this->getMock('OCP\IRequest'), $this->getMock('OCP\IUserSession'));
+		$factory = new \OC\L10N\Factory($this->getMock('OCP\IConfig'), $this->getMock('OCP\IRequest'), $this->getMock('OCP\IUserSession'), \OC::$SERVERROOT);
 		$l = $factory->get('lib', 'de');
 		$this->assertEquals('de', $l->getLanguageCode());
 	}
diff --git a/tests/lib/l10n/l10ntest.php b/tests/lib/l10n/l10ntest.php
index 0d175954bc..227e07056a 100644
--- a/tests/lib/l10n/l10ntest.php
+++ b/tests/lib/l10n/l10ntest.php
@@ -31,7 +31,7 @@ class L10nTest extends TestCase {
 		$request = $this->getMock('OCP\IRequest');
 		/** @var IUserSession $userSession */
 		$userSession = $this->getMock('OCP\IUserSession');
-		return new Factory($config, $request, $userSession);
+		return new Factory($config, $request, $userSession, \OC::$SERVERROOT);
 	}
 
 	public function testGermanPluralTranslations() {