diff --git a/src/Symfony/Component/Translation/Command/XliffLintCommand.php b/src/Symfony/Component/Translation/Command/XliffLintCommand.php
index 9bea4d9499..3c2cc9efde 100644
--- a/src/Symfony/Component/Translation/Command/XliffLintCommand.php
+++ b/src/Symfony/Component/Translation/Command/XliffLintCommand.php
@@ -124,7 +124,9 @@ EOF
             $normalizedLocale = preg_quote(str_replace('-', '_', $targetLanguage), '/');
             // strict file names require translation files to be named '____.locale.xlf'
             // otherwise, both '____.locale.xlf' and 'locale.____.xlf' are allowed
-            $expectedFilenamePattern = $this->requireStrictFileNames ? sprintf('/^.*\.%s\.xlf/', $normalizedLocale) : sprintf('/^(.*\.%s\.xlf|%s\..*\.xlf)/', $normalizedLocale, $normalizedLocale);
+            // also, the regexp matching must be case-insensitive, as defined for 'target-language' values
+            // http://docs.oasis-open.org/xliff/v1.2/os/xliff-core.html#target-language
+            $expectedFilenamePattern = $this->requireStrictFileNames ? sprintf('/^.*\.(?i:%s)\.xlf/', $normalizedLocale) : sprintf('/^(.*\.(?i:%s)\.xlf|(?i:%s)\..*\.xlf)/', $normalizedLocale, $normalizedLocale);
 
             if (0 === preg_match($expectedFilenamePattern, basename($file))) {
                 $errors[] = [
diff --git a/src/Symfony/Component/Translation/Tests/Command/XliffLintCommandTest.php b/src/Symfony/Component/Translation/Tests/Command/XliffLintCommandTest.php
index 516d98af53..df2e2f0951 100644
--- a/src/Symfony/Component/Translation/Tests/Command/XliffLintCommandTest.php
+++ b/src/Symfony/Component/Translation/Tests/Command/XliffLintCommandTest.php
@@ -94,6 +94,17 @@ class XliffLintCommandTest extends TestCase
         $this->assertContains('There is a mismatch between the language included in the file name ("messages.en.xlf") and the "es" value used in the "target-language" attribute of the file.', trim($tester->getDisplay()));
     }
 
+    public function testLintTargetLanguageIsCaseInsensitive()
+    {
+        $tester = $this->createCommandTester();
+        $filename = $this->createFile('note', 'zh-cn', 'messages.zh_CN.xlf');
+
+        $tester->execute(['filename' => $filename], ['decorated' => false]);
+
+        $this->assertEquals(0, $tester->getStatusCode());
+        $this->assertContains('[OK] All 1 XLIFF files contain valid syntax.', trim($tester->getDisplay()));
+    }
+
     /**
      * @expectedException \RuntimeException
      */