diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index cebe699..5926024 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -189,6 +189,18 @@ public function removeClass() {
   }
 
   /**
+   * Checks if the class array has the given CSS class.
+   *
+   * @param string $class
+   *   CSS class to check for.
+   *
+   * @return bool
+   */
+  public function hasClass($class) {
+    return in_array($class, $this->storage['class']->value());
+  }
+
+  /**
    * Implements the magic __toString() method.
    */
   public function __toString() {
diff --git a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
index b04eb51..49da086 100644
--- a/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
+++ b/core/tests/Drupal/Tests/Core/Template/AttributeTest.php
@@ -141,6 +141,21 @@ public function testRemoveClasses() {
   }
 
   /**
+   * Tests checking for class names with the Attribute method.
+   * @covers ::hasClass()
+   */
+  public function testHasClass() {
+    // Add a class to check for.
+    $classes = array('we-totally-have-this-class');
+    $attribute = new Attribute(array('class' => $classes));
+
+    // Check that this class exists.
+    $this->assertTrue($attribute->hasClass('we-totally-have-this-class'));
+    // Check that this class does not exist.
+    $this->assertFalse($attribute->hasClass('a-class-nowhere-to-be-found'));
+  }
+
+  /**
    * Tests removing class attributes with the Attribute helper methods.
    * @covers ::removeClass()
    * @covers ::addClass()