diff --git a/core/modules/taxonomy/src/Plugin/EntityReferenceSelection/TermSelection.php b/core/modules/taxonomy/src/Plugin/EntityReferenceSelection/TermSelection.php
index 3b1c2368d5ec9f53b0ab68ba8a2921b0aee0f9d0..7dd4aa2d6e57d68e85c4c5b6b6d8a414b2677d67 100644
--- a/core/modules/taxonomy/src/Plugin/EntityReferenceSelection/TermSelection.php
+++ b/core/modules/taxonomy/src/Plugin/EntityReferenceSelection/TermSelection.php
@@ -49,6 +49,7 @@ public function buildConfigurationForm(array $form, FormStateInterface $form_sta
    */
   public function getReferenceableEntities($match = NULL, $match_operator = 'CONTAINS', $limit = 0) {
     if ($match || $limit) {
+      $this->configuration['handler_settings']['sort'] = ['field' => 'name', 'direction' => 'asc'];
       return parent::getReferenceableEntities($match, $match_operator, $limit);
     }
 
diff --git a/core/modules/taxonomy/src/Tests/TermAutocompleteTest.php b/core/modules/taxonomy/src/Tests/TermAutocompleteTest.php
new file mode 100644
index 0000000000000000000000000000000000000000..7ff519df94034f6c810eafde6dfb1ca18c9315fa
--- /dev/null
+++ b/core/modules/taxonomy/src/Tests/TermAutocompleteTest.php
@@ -0,0 +1,204 @@
+<?php
+
+namespace Drupal\taxonomy\Tests;
+
+use Drupal\Component\Utility\Unicode;
+use Drupal\Core\Entity\Entity\EntityFormDisplay;
+use Drupal\Core\Entity\Entity\EntityViewDisplay;
+use Drupal\Core\Field\FieldStorageDefinitionInterface;
+use Drupal\field\Entity\FieldConfig;
+use Drupal\field\Entity\FieldStorageConfig;
+
+/**
+ * Tests the autocomplete implementation of the taxonomy class.
+ *
+ * @group taxonomy
+ */
+class TermAutocompleteTest extends TaxonomyTestBase {
+
+  /**
+   * The vocabulary.
+   *
+   * @var \Drupal\taxonomy\Entity\Vocabulary
+   */
+  protected $vocabulary;
+
+  /**
+   * The field to add to the content type for the taxonomy terms.
+   *
+   * @var string
+   */
+  protected $fieldName;
+
+  /**
+   * The admin user.
+   *
+   * @var \Drupal\user\Entity\User
+   */
+  protected $adminUser;
+
+  /**
+   * The autocomplete URL to call.
+   *
+   * @var string
+   */
+  protected $autocompleteUrl;
+
+  /**
+   * The term IDs indexed by term names.
+   *
+   * @var array
+   */
+  protected $termIds;
+
+  /**
+   * {@inheritdoc}
+   */
+  protected function setUp() {
+    parent::setUp();
+
+    // Create a vocabulary.
+    $this->vocabulary = $this->createVocabulary();
+
+    // Create 11 terms, which have some sub-string in common, in a
+    // non-alphabetical order, so that we will have more than 10 matches later
+    // when we test the correct number of results is returned, and we can test
+    // the order of the results. The location of the sub-string to match varies
+    // also, since it should not be necessary to start with the sub-string to
+    // match it. Save term IDs to reuse later.
+    $termNames = [
+      'aaa 20 bbb',
+      'aaa 70 bbb',
+      'aaa 10 bbb',
+      'aaa 12 bbb',
+      'aaa 40 bbb',
+      'aaa 11 bbb',
+      'aaa 30 bbb',
+      'aaa 50 bbb',
+      'aaa 80',
+      'aaa 90',
+      'bbb 60 aaa',
+    ];
+    foreach ($termNames as $termName) {
+      $term = $this->createTerm($this->vocabulary, ['name' => $termName]);
+      $this->termIds[$termName] = $term->id();
+    }
+
+    // Create a taxonomy_term_reference field on the article Content Type that
+    // uses a taxonomy_autocomplete widget.
+    $this->fieldName = Unicode::strtolower($this->randomMachineName());
+    FieldStorageConfig::create([
+      'field_name' => $this->fieldName,
+      'entity_type' => 'node',
+      'type' => 'entity_reference',
+      'cardinality' => FieldStorageDefinitionInterface::CARDINALITY_UNLIMITED,
+      'settings' => [
+        'target_type' => 'taxonomy_term',
+      ],
+    ])->save();
+    FieldConfig::create([
+      'field_name' => $this->fieldName,
+      'bundle' => 'article',
+      'entity_type' => 'node',
+      'settings' => [
+        'handler' => 'default',
+        'handler_settings' => [
+          // Restrict selection of terms to a single vocabulary.
+          'target_bundles' => [
+            $this->vocabulary->id() => $this->vocabulary->id(),
+          ],
+        ],
+      ],
+    ])->save();
+    EntityFormDisplay::load('node.article.default')
+      ->setComponent($this->fieldName, [
+        'type' => 'entity_reference_autocomplete',
+      ])
+      ->save();
+    EntityViewDisplay::load('node.article.default')
+      ->setComponent($this->fieldName, [
+        'type' => 'entity_reference_label',
+      ])
+      ->save();
+
+    // Create a user and then login.
+    $this->adminUser = $this->drupalCreateUser(['create article content']);
+    $this->drupalLogin($this->adminUser);
+
+    // Retrieve the autocomplete url.
+    $this->drupalGet('node/add/article');
+    $result = $this->xpath('//input[@name="' . $this->fieldName . '[0][target_id]"]');
+    $this->autocompleteUrl = $this->getAbsoluteUrl($result[0]['data-autocomplete-path']);
+  }
+
+  /**
+   * Tests that the autocomplete method returns the good number of results.
+   *
+   * @see \Drupal\taxonomy\Controller\TermAutocompleteController::autocomplete()
+   */
+  public function testAutocompleteCountResults() {
+    // Test that no matching term found.
+    $data = $this->drupalGetJSON(
+      $this->autocompleteUrl,
+      ['query' => ['q' => 'zzz']]
+    );
+    $this->assertTrue(empty($data), 'Autocomplete returned no results');
+
+    // Test that only one matching term found, when only one matches.
+    $data = $this->drupalGetJSON(
+      $this->autocompleteUrl,
+      ['query' => ['q' => 'aaa 10']]
+    );
+    $this->assertEqual(1, count($data), 'Autocomplete returned 1 result');
+
+    // Test the correct number of matches when multiple are partial matches.
+    $data = $this->drupalGetJSON(
+      $this->autocompleteUrl,
+      ['query' => ['q' => 'aaa 1']]
+    );
+    $this->assertEqual(3, count($data), 'Autocomplete returned 3 results');
+
+    // Tests that only 10 results are returned, even if there are more than 10
+    // matches.
+    $data = $this->drupalGetJSON(
+      $this->autocompleteUrl,
+      ['query' => ['q' => 'aaa']]
+    );
+    $this->assertEqual(10, count($data), 'Autocomplete returned only 10 results (for over 10 matches)');
+  }
+
+  /**
+   * Tests that the autocomplete method returns properly ordered results.
+   *
+   * @see \Drupal\taxonomy\Controller\TermAutocompleteController::autocomplete()
+   */
+  public function testAutocompleteOrderedResults() {
+    $expectedResults = [
+      'aaa 10 bbb',
+      'aaa 11 bbb',
+      'aaa 12 bbb',
+      'aaa 20 bbb',
+      'aaa 30 bbb',
+      'aaa 40 bbb',
+      'aaa 50 bbb',
+      'aaa 70 bbb',
+      'bbb 60 aaa',
+    ];
+    // Build $expected to match the autocomplete results.
+    $expected = [];
+    foreach ($expectedResults as $termName) {
+      $expected[] = [
+        'value' => $termName . ' (' . $this->termIds[$termName] . ')',
+        'label' => $termName
+      ];
+    }
+
+    $data = $this->drupalGetJSON(
+      $this->autocompleteUrl,
+      ['query' => ['q' => 'bbb']]
+    );
+
+    $this->assertIdentical($expected, $data);
+  }
+
+}