diff --git a/core/lib/Drupal/Core/Config/FileStorage.php b/core/lib/Drupal/Core/Config/FileStorage.php
index 88af39e..69c18cb 100644
--- a/core/lib/Drupal/Core/Config/FileStorage.php
+++ b/core/lib/Drupal/Core/Config/FileStorage.php
@@ -94,7 +94,7 @@ public function exists($name) {
    */
   public function read($name) {
     if (!$this->exists($name)) {
-      return FALSE;
+      return NULL;
     }
     $data = file_get_contents($this->getFilePath($name));
     try {
diff --git a/core/lib/Drupal/Core/Config/StorageInterface.php b/core/lib/Drupal/Core/Config/StorageInterface.php
index f6145b8..5138144 100644
--- a/core/lib/Drupal/Core/Config/StorageInterface.php
+++ b/core/lib/Drupal/Core/Config/StorageInterface.php
@@ -37,9 +37,9 @@ public function exists($name);
    * @param string $name
    *   The name of a configuration object to load.
    *
-   * @return array|bool
+   * @return array
    *   The configuration data stored for the configuration object name. If no
-   *   configuration data exists for the given name, FALSE is returned.
+   *   configuration data exists for the given name, NULL is returned.
    */
   public function read($name);
 
diff --git a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
index e01e505..ab962a3 100644
--- a/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
+++ b/core/tests/Drupal/Tests/Core/Config/CachedStorageTest.php
@@ -124,7 +124,7 @@ public function testGetMultipleOnPartiallyPrimedCache() {
 
     // Ensure that the a missing file is cached.
     $entry = $cache->get('config.does_not_exist');
-    $this->assertFalse($entry->data);
+    $this->assertNull($entry->data);
 
     // Ensure that the a file containing data is cached.
     $entry = $cache->get('config.exists_not_cached');
@@ -141,15 +141,15 @@ public function testReadNonExistentFileCacheMiss() {
     $storage->expects($this->once())
             ->method('read')
             ->with($name)
-            ->will($this->returnValue(FALSE));
+            ->will($this->returnValue(NULL));
 
     $cachedStorage = new CachedStorage($storage, $cache);
 
-    $this->assertFalse($cachedStorage->read($name));
+    $this->assertNull($cachedStorage->read($name));
 
     // Ensure that the a missing file is cached.
     $entry = $cache->get('config.does_not_exist');
-    $this->assertFalse($entry->data);
+    $this->assertNull($entry->data);
   }
 
   /**
@@ -158,14 +158,14 @@ public function testReadNonExistentFileCacheMiss() {
   public function testReadNonExistentFileCached() {
     $name = 'config.does_not_exist';
     $cache = new MemoryBackend(__FUNCTION__);
-    $cache->set($name, FALSE);
+    $cache->set($name, NULL);
 
     $storage = $this->getMock('Drupal\Core\Config\StorageInterface');
     $storage->expects($this->never())
             ->method('read');
 
     $cachedStorage = new CachedStorage($storage, $cache);
-    $this->assertFalse($cachedStorage->read($name));
+    $this->assertNull($cachedStorage->read($name));
   }
 
 }