diff --git a/.travis.yml b/.travis.yml
index 13f201c6f..0e8536ba5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,6 +21,7 @@ install:
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/inky-extra && travis_retry composer install)
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/intl-extra && travis_retry composer install)
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/markdown-extra && travis_retry composer install)
+    - ([[ $TRAVIS_PHP_VERSION < 7.2 ]] || cd extra/string-extra && travis_retry composer install)
 
 script:
     - ./vendor/bin/simple-phpunit
@@ -29,6 +30,7 @@ script:
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/inky-extra && ./vendor/bin/simple-phpunit)
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/intl-extra && ./vendor/bin/simple-phpunit)
     - ([[ $TRAVIS_PHP_VERSION = 7.0 ]] || cd extra/markdown-extra && ./vendor/bin/simple-phpunit)
+    - ([[ $TRAVIS_PHP_VERSION < 7.2 ]] || cd extra/string-extra && ./vendor/bin/simple-phpunit)
 
 jobs:
     fast_finish: true
diff --git a/extra/string-extra/.gitignore b/extra/string-extra/.gitignore
new file mode 100644
index 000000000..76367ee5b
--- /dev/null
+++ b/extra/string-extra/.gitignore
@@ -0,0 +1,4 @@
+vendor/
+composer.lock
+phpunit.xml
+.phpunit.result.cache
diff --git a/extra/string-extra/LICENSE b/extra/string-extra/LICENSE
new file mode 100644
index 000000000..1a1869751
--- /dev/null
+++ b/extra/string-extra/LICENSE
@@ -0,0 +1,19 @@
+Copyright (c) 2019 Fabien Potencier
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is furnished
+to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
diff --git a/extra/string-extra/README.md b/extra/string-extra/README.md
new file mode 100644
index 000000000..cef5799d5
--- /dev/null
+++ b/extra/string-extra/README.md
@@ -0,0 +1,10 @@
+String Extension
+================
+
+This package is a Twig extension that provides integration with the Symfony String component.
+
+It provides a single [`u`][1] filter that wraps a text in a `UnicodeString` object to give access to [methods of the class](https://symfony.com/doc/current/components/string.html).
+
+`{{ 'Symfony String + Twig = <3'|u.wordwrap(5) }}`
+
+[1]: https://twig.symfony.com/u
diff --git a/extra/string-extra/composer.json b/extra/string-extra/composer.json
new file mode 100644
index 000000000..8a9e27f60
--- /dev/null
+++ b/extra/string-extra/composer.json
@@ -0,0 +1,39 @@
+{
+    "name": "twig/string-extra",
+    "type": "library",
+    "description": "A Twig extension for Symfony String",
+    "keywords": ["twig", "html", "string", "unicode"],
+    "homepage": "https://twig.symfony.com",
+    "license": "MIT",
+    "authors": [
+        {
+            "name": "Fabien Potencier",
+            "email": "fabien@symfony.com",
+            "homepage": "http://fabien.potencier.org",
+            "role": "Lead Developer"
+        }
+    ],
+    "require": {
+        "php": "^7.2.9",
+        "symfony/string": "^5.0@dev",
+        "twig/twig": "^2.4|^3.0"
+    },
+    "require-dev": {
+        "symfony/phpunit-bridge": "^4.4@dev"
+    },
+    "autoload": {
+        "psr-4" : {
+            "Twig\\Extra\\String\\" : "src/"
+        }
+    },
+    "autoload-dev": {
+        "psr-4" : {
+            "Twig\\Extra\\String\\Tests\\" : "tests/"
+        }
+    },
+    "extra": {
+        "branch-alias": {
+            "dev-master": "2.12-dev"
+        }
+    }
+}
diff --git a/extra/string-extra/phpunit.xml.dist b/extra/string-extra/phpunit.xml.dist
new file mode 100644
index 000000000..4b84ca9c2
--- /dev/null
+++ b/extra/string-extra/phpunit.xml.dist
@@ -0,0 +1,30 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.2/phpunit.xsd"
+         backupGlobals="false"
+         colors="true"
+         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
+>
+    <php>
+        <ini name="error_reporting" value="-1" />
+    </php>
+
+    <testsuites>
+        <testsuite name="Twig Markdown Extension Test Suite">
+            <directory>./tests/</directory>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist>
+            <directory>./</directory>
+            <exclude>
+                <directory>./tests</directory>
+                <directory>./vendor</directory>
+            </exclude>
+        </whitelist>
+    </filter>
+</phpunit>
diff --git a/extra/string-extra/src/StringExtension.php b/extra/string-extra/src/StringExtension.php
new file mode 100644
index 000000000..ae99d971f
--- /dev/null
+++ b/extra/string-extra/src/StringExtension.php
@@ -0,0 +1,31 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extra\String;
+
+use Symfony\Component\String\UnicodeString;
+use Twig\Extension\AbstractExtension;
+use Twig\TwigFilter;
+
+final class StringExtension extends AbstractExtension
+{
+    public function getFilters()
+    {
+        return [
+            new TwigFilter('u', [$this, 'createUnicodeString']),
+        ];
+    }
+
+    public function createUnicodeString(string $text): UnicodeString
+    {
+        return new UnicodeString($text);
+    }
+}
diff --git a/extra/string-extra/tests/Fixtures/string.test b/extra/string-extra/tests/Fixtures/string.test
new file mode 100644
index 000000000..945af3355
--- /dev/null
+++ b/extra/string-extra/tests/Fixtures/string.test
@@ -0,0 +1,17 @@
+--TEST--
+"u" filter
+--TEMPLATE--
+{{ 'Symfony String + Twig = <3'|u|raw }}
+
+{{ 'Symfony String + Twig = <3'|u.wordwrap(5)|raw }}
+
+--DATA--
+return []
+--EXPECT--
+Symfony String + Twig = <3
+
+Symfony
+String
++
+Twig
+= <3
diff --git a/extra/string-extra/tests/IntegrationTest.php b/extra/string-extra/tests/IntegrationTest.php
new file mode 100644
index 000000000..1c0aea419
--- /dev/null
+++ b/extra/string-extra/tests/IntegrationTest.php
@@ -0,0 +1,30 @@
+<?php
+
+/*
+ * This file is part of Twig.
+ *
+ * (c) Fabien Potencier
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Twig\Extra\Markdown\Tests;
+
+use Twig\Extra\String\StringExtension;
+use Twig\Test\IntegrationTestCase;
+
+class IntegrationTest extends IntegrationTestCase
+{
+    public function getExtensions()
+    {
+        return [
+            new StringExtension(),
+        ];
+    }
+
+    public function getFixturesDir()
+    {
+        return __DIR__.'/Fixtures/';
+    }
+}