diff -u b/core/lib/Drupal/Core/Render/Element/Radio.php b/core/lib/Drupal/Core/Render/Element/Radio.php
--- b/core/lib/Drupal/Core/Render/Element/Radio.php
+++ b/core/lib/Drupal/Core/Render/Element/Radio.php
@@ -54,16 +54,23 @@
     $element['#attributes']['type'] = 'radio';
     Element::setAttributes($element, array('id', 'name', '#return_value' => 'value'));
 
-    if (isset($element['#return_value']) && $element['#value'] !== FALSE) {
+    if (isset($element['#return_value'])) {
       // To avoid auto-casting during '==' we convert int 0 to '0' for both
       // operands. It will prevent wrong true-checking for both cases: 0 ==
       // 'string' and 'string' == 0.
-      if ($element['#value'] === 0) {
+      if ($element['#value'] === 0 || $element['#value'] === FALSE) {
         $element['#value'] = '0';
       }
-      if ($element['#return_value'] === 0) {
+      elseif ($element['#value'] === TRUE) {
+        $element['#value'] = '1';
+      }
+      if ($element['#return_value'] === 0 || $element['#return_value'] === FALSE) {
         $element['#return_value'] = '0';
       }
+      elseif ($element['#return_value'] === TRUE) {
+        $element['#return_value'] = '1';
+      }
+
       if ($element['#value'] == $element['#return_value']) {
         $element['#attributes']['checked'] = 'checked';
       }
diff -u b/core/modules/system/src/Tests/Form/ElementTest.php b/core/modules/system/src/Tests/Form/ElementTest.php
--- b/core/modules/system/src/Tests/Form/ElementTest.php
+++ b/core/modules/system/src/Tests/Form/ElementTest.php
@@ -100,6 +100,12 @@
     $elements = $this->xpath('//input[@name="radios-string" and @checked]');
     $this->assertEqual(count($elements), 1);
     $this->assertIdentical((string) $elements[0]['value'], 'bar');
+    $elements = $this->xpath('//input[@name="radios-boolean-true" and @checked]');
+    $this->assertEqual(count($elements), 1);
+    $this->assertIdentical((string) $elements[0]['value'], '1');
+    $elements = $this->xpath('//input[@name="radios-boolean-false" and @checked]');
+    $this->assertEqual(count($elements), 1);
+    $this->assertIdentical((string) $elements[0]['value'], '0');
   }
 
   /**
diff -u b/core/modules/system/tests/modules/form_test/src/Form/FormTestRadiosCheckedForm.php b/core/modules/system/tests/modules/form_test/src/Form/FormTestRadiosCheckedForm.php
--- b/core/modules/system/tests/modules/form_test/src/Form/FormTestRadiosCheckedForm.php
+++ b/core/modules/system/tests/modules/form_test/src/Form/FormTestRadiosCheckedForm.php
@@ -51,6 +51,26 @@
       ),
       '#default_value' => 'bar',
     );
+    $form['radios-boolean-true'] = array(
+      '#type' => 'radios',
+      '#title' => 'Radios',
+      '#options' => array(
+        'All' => '- Any -',
+        1 => 'True',
+        0 => 'False',
+      ),
+      '#default_value' => TRUE,
+    );
+    $form['radios-boolean-false'] = array(
+      '#type' => 'radios',
+      '#title' => 'Radios',
+      '#options' => array(
+        'All' => '- Any -',
+        1 => 'True',
+        0 => 'False',
+      ),
+      '#default_value' => FALSE,
+    );
 
     $form['submit'] = array('#type' => 'submit', '#value' => 'Submit');