diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 62fa0bb8e0..c4807313d9 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.12 under development
 --------------------------
 
+- Bug #7946 Fixed a bug when the `form` attribute was not propagated to the hidden input of the checkbox (Kolyunya)
 - Bug #13087: Fixed getting active validators for safe attribute (developeruz)
 - Bug #13571: Fix `yii\db\mssql\QueryBuilder::checkIntegrity` for all tables (boboldehampsink)
 - Bug #11230: Include `defaultRoles` in `yii\rbac\DbManager->getRolesByUser()` results (developeruz)
diff --git a/framework/helpers/BaseHtml.php b/framework/helpers/BaseHtml.php
index 6e6a9c27df..4702aff4e1 100644
--- a/framework/helpers/BaseHtml.php
+++ b/framework/helpers/BaseHtml.php
@@ -60,6 +60,7 @@ class BaseHtml
         'href',
         'src',
         'srcset',
+        'form',
         'action',
         'method',
 
@@ -742,7 +743,11 @@ class BaseHtml
         $value = array_key_exists('value', $options) ? $options['value'] : '1';
         if (isset($options['uncheck'])) {
             // add a hidden field so that if the checkbox is not selected, it still submits a value
-            $hidden = static::hiddenInput($name, $options['uncheck']);
+            $hiddenOptions = [];
+            if (isset($options['form'])) {
+                $hiddenOptions['form'] = $options['form'];
+            }
+            $hidden = static::hiddenInput($name, $options['uncheck'], $hiddenOptions);
             unset($options['uncheck']);
         } else {
             $hidden = '';
diff --git a/tests/framework/helpers/HtmlTest.php b/tests/framework/helpers/HtmlTest.php
index be457c6835..55e74ec00b 100644
--- a/tests/framework/helpers/HtmlTest.php
+++ b/tests/framework/helpers/HtmlTest.php
@@ -378,6 +378,13 @@ class HtmlTest extends TestCase
             'label' => 'ccc',
             'value' => 2,
         ]));
+        $this->assertEquals('<input type="hidden" name="test" value="0" form="test-form"><label><input type="checkbox" class="a" name="test" value="2" form="test-form" checked> ccc</label>', Html::checkbox('test', true, [
+            'class' => 'a',
+            'uncheck' => '0',
+            'label' => 'ccc',
+            'value' => 2,
+            'form' => 'test-form',
+        ]));
     }
 
     public function testDropDownList()