diff --git a/core/lib/Drupal/Core/Entity/Element/EntityAutocomplete.php b/core/lib/Drupal/Core/Entity/Element/EntityAutocomplete.php
index 2cb823aaed3b320cfcf8034536c53c2693be0b8d..b17813758f6a6941c038006833dd609fe58dfe74 100644
--- a/core/lib/Drupal/Core/Entity/Element/EntityAutocomplete.php
+++ b/core/lib/Drupal/Core/Entity/Element/EntityAutocomplete.php
@@ -203,7 +203,8 @@ public static function processEntityAutocomplete(array &$element, FormStateInter
   public static function validateEntityAutocomplete(array &$element, FormStateInterface $form_state, array &$complete_form) {
     $value = NULL;
 
-    if (!empty($element['#value'])) {
+    // Check the value for emptiness, but allow the use of (string) "0".
+    if ((!empty($element['#value']) || (is_string($element['#value']) && strlen($element['#value'])))) {
       $options = $element['#selection_settings'] + [
         'target_type' => $element['#target_type'],
         'handler' => $element['#selection_handler'],
diff --git a/core/modules/system/src/Controller/EntityAutocompleteController.php b/core/modules/system/src/Controller/EntityAutocompleteController.php
index a49da373406f6c2e8c8947d245bdf1371a88cfbc..860ab7f846edfd695d2f8a895631058b9461564a 100644
--- a/core/modules/system/src/Controller/EntityAutocompleteController.php
+++ b/core/modules/system/src/Controller/EntityAutocompleteController.php
@@ -77,8 +77,12 @@ public static function create(ContainerInterface $container) {
    */
   public function handleAutocomplete(Request $request, $target_type, $selection_handler, $selection_settings_key) {
     $matches = [];
+
     // Get the typed string from the URL, if it exists.
-    if ($input = $request->query->get('q')) {
+    $input = $request->query->get('q');
+
+    // Check this string for emptiness, but allow any non-empty string.
+    if (is_string($input) && strlen($input)) {
       $tag_list = Tags::explode($input);
       $typed_string = !empty($tag_list) ? mb_strtolower(array_pop($tag_list)) : '';
 
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/Element/EntityAutocompleteElementFormTest.php b/core/tests/Drupal/KernelTests/Core/Entity/Element/EntityAutocompleteElementFormTest.php
index 107ec0e7a30624cf190dcbec8c432c6d4617ae03..f4b101f2646383fa9c853e826e6642c1c6d57b69 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/Element/EntityAutocompleteElementFormTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/Element/EntityAutocompleteElementFormTest.php
@@ -92,6 +92,12 @@ protected function setUp(): void {
       $entity->save();
       $this->referencedEntities[] = $entity;
     }
+
+    $entity = EntityTest::create([
+      'name' => '0',
+    ]);
+    $entity->save();
+    $this->referencedEntities[] = $entity;
   }
 
   /**
@@ -184,6 +190,11 @@ public function buildForm(array $form, FormStateInterface $form_state) {
       '#tags' => TRUE,
     ];
 
+    $form['single_name_0'] = [
+      '#type' => 'entity_autocomplete',
+      '#target_type' => 'entity_test',
+    ];
+
     return $form;
   }
 
@@ -211,6 +222,7 @@ public function testValidEntityAutocompleteElement() {
         'tags_autocreate_specific_uid' => $this->getAutocompleteInput($this->referencedEntities[0]) . ', tags - autocreated entity label with specific uid, ' . $this->getAutocompleteInput($this->referencedEntities[1]),
         'single_string_id' => $this->getAutocompleteInput($this->referencedEntities[2]),
         'tags_string_id' => $this->getAutocompleteInput($this->referencedEntities[2]) . ', ' . $this->getAutocompleteInput($this->referencedEntities[3]),
+        'single_name_0' => $this->referencedEntities[4]->label(),
       ]);
     $form_builder = $this->container->get('form_builder');
     $form_builder->submitForm($this, $form_state);
@@ -271,6 +283,9 @@ public function testValidEntityAutocompleteElement() {
       ['target_id' => $this->referencedEntities[3]->id()],
     ];
     $this->assertEquals($expected, $form_state->getValue('tags_string_id'));
+
+    // Test the 'single_name_0' element.
+    $this->assertEquals($this->referencedEntities[4]->id(), $form_state->getValue('single_name_0'));
   }
 
   /**
diff --git a/core/tests/Drupal/KernelTests/Core/Entity/EntityAutocompleteTest.php b/core/tests/Drupal/KernelTests/Core/Entity/EntityAutocompleteTest.php
index 2b8058a45a5eb8ebae3607056649d11e667b0869..5b41f448bf31510ab8ca6d9372d02de591c696b1 100644
--- a/core/tests/Drupal/KernelTests/Core/Entity/EntityAutocompleteTest.php
+++ b/core/tests/Drupal/KernelTests/Core/Entity/EntityAutocompleteTest.php
@@ -106,9 +106,11 @@ public function testEntityReferenceAutocompletion() {
     ];
     $this->assertSame($target, reset($data), 'Autocomplete returns an entity label containing a comma and a slash.');
 
-    $input = '';
-    $data = $this->getAutocompleteResult($input);
-    $this->assertSame([], $data, 'Autocomplete of empty string returns empty result');
+    // Test empty input.
+    foreach (['', NULL, FALSE, 0, 0.0] as $input) {
+      $data = $this->getAutocompleteResult($input);
+      $this->assertSame([], $data, 'Autocomplete of empty input returns empty result');
+    }
 
     $input = ',';
     $data = $this->getAutocompleteResult($input);
@@ -130,6 +132,12 @@ public function testEntityReferenceAutocompletion() {
     $this->assertSame(Html::escape($entity_1->name->value), $data[0]['label'], 'Autocomplete returned the first matching entity');
     $this->assertSame(Html::escape($entity_2->name->value), $data[1]['label'], 'Autocomplete returned the second matching entity');
     $this->assertSame(Html::escape($entity_3->name->value), $data[2]['label'], 'Autocomplete returned the third matching entity');
+
+    // Try to autocomplete an entity label with the '0' character.
+    $input = '0';
+    $data = $this->getAutocompleteResult($input);
+    $this->assertSame(Html::escape($entity_1->name->value), $data[0]['label'], 'Autocomplete returned the first matching entity');
+    $this->assertSame(Html::escape($entity_2->name->value), $data[1]['label'], 'Autocomplete returned the second matching entity');
   }
 
   /**