diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index a2b0d05..8ea0532 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -243,6 +243,7 @@ Yii Framework 2 Change Log
 - Bug #9046: Fixed problem with endless error loop when an error occurred after sending a stream or file download response to the user (cebe)
 - Bug #9059: Fixed PHP Notice in error handler view (dynasource, andrewnester, samdark)
 - Bug #9063: Workaround for MySQL losing table case when adding index (sebathi)
+- Bug #9074: Fixed JS call `$('#grid').yiiGridView('getSelectedRows')` when `GridView::$showHeader` is set to false (NekitoSP, silverfire)
 - Bug #9076: Fixed `yii\filters\PageCache` not using the configured duration and dependency when caching the response data (kidol)
 - Bug #9091: `UrlManager::createUrl()` did not create correct url when defaults were used, internal cache is now skipped in certain situations (cebe)
 - Bug #9127, #9128: Fixed MSSQL `QueryBuilder::renameColumn()` and `QueryBuilder::renameTable()` escaping (sitawit)
diff --git a/framework/assets/yii.gridView.js b/framework/assets/yii.gridView.js
index d03e913..8306666 100644
--- a/framework/assets/yii.gridView.js
+++ b/framework/assets/yii.gridView.js
@@ -55,7 +55,12 @@
             return this.each(function () {
                 var $e = $(this);
                 var settings = $.extend({}, defaults, options || {});
-                gridData[$e.attr('id')] = {settings: settings};
+                var id = $e.attr('id');
+                if (gridData[id] === undefined) {
+                    gridData[id] = {};
+                }
+
+                gridData[id] = $.extend(gridData[id], {settings: settings});
 
                 var enterPressed = false;
                 $(document).off('change.yiiGridView keydown.yiiGridView', settings.filterSelector)
@@ -142,6 +147,9 @@
         setSelectionColumn: function (options) {
             var $grid = $(this);
             var id = $(this).attr('id');
+            if (gridData.id === undefined) {
+                gridData[id] = {};
+            }
             gridData[id].selectionColumn = options.name;
             if (!options.multiple || !options.checkAll) {
                 return;
diff --git a/framework/grid/CheckboxColumn.php b/framework/grid/CheckboxColumn.php
index 57bbc05..9b5a17d 100644
--- a/framework/grid/CheckboxColumn.php
+++ b/framework/grid/CheckboxColumn.php
@@ -10,6 +10,7 @@ namespace yii\grid;
 use Closure;
 use yii\base\InvalidConfigException;
 use yii\helpers\Html;
+use yii\helpers\Json;
 
 /**
  * CheckboxColumn displays a column of checkboxes in a grid view.
@@ -82,14 +83,7 @@ class CheckboxColumn extends Column
             $this->name .= '[]';
         }
 
-        $name = $this->grid->showHeader ? $this->getHeaderCheckBoxName() : NULL;
-        $id = $this->grid->options['id'];
-        $options = json_encode([
-            'name' => $this->name,
-            'multiple' => $this->multiple,
-            'checkAll' => $name,
-        ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
-        $this->grid->getView()->registerJs("jQuery('#$id').yiiGridView('setSelectionColumn', $options);");
+        $this->registerClientScript();
     }
 
     /**
@@ -100,28 +94,10 @@ class CheckboxColumn extends Column
      */
     protected function renderHeaderCellContent()
     {
-        $name = $this->name;
-        if (substr_compare($name, '[]', -2, 2) === 0) {
-            $name = substr($name, 0, -2);
-        }
-        if (substr_compare($name, ']', -1, 1) === 0) {
-            $name = substr($name, 0, -1) . '_all]';
-        } else {
-            $name .= '_all';
-        }
-
-        $id = $this->grid->options['id'];
-        $options = json_encode([
-            'name' => $this->name,
-            'multiple' => $this->multiple,
-            'checkAll' => $name,
-        ], JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE);
-        $this->grid->getView()->registerJs("jQuery('#$id').yiiGridView('setSelectionColumn', $options);");
-
         if ($this->header !== null || !$this->multiple) {
             return parent::renderHeaderCellContent();
         } else {
-            return Html::checkbox($name, false, ['class' => 'select-on-check-all']);
+            return Html::checkbox($this->getHeaderCheckBoxName(), false, ['class' => 'select-on-check-all']);
         }
     }
 
@@ -137,7 +113,7 @@ class CheckboxColumn extends Column
         }
 
         if (!isset($options['value'])) {
-            $options['value'] = is_array($key) ? json_encode($key, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE) : $key;
+            $options['value'] = is_array($key) ? Json::encode($key) : $key;
         }
 
         return Html::checkbox($this->name, !empty($options['checked']), $options);
@@ -146,9 +122,35 @@ class CheckboxColumn extends Column
     /**
      * Returns header checkbox name
      * @return string header checkbox name
+     * @since 2.0.8
      */
-    private function getHeaderCheckBoxName()
+    protected function getHeaderCheckBoxName()
     {
-        return rtrim($this->name, '[]') . '_all';
+        $name = $this->name;
+        if (substr_compare($name, '[]', -2, 2) === 0) {
+            $name = substr($name, 0, -2);
+        }
+        if (substr_compare($name, ']', -1, 1) === 0) {
+            $name = substr($name, 0, -1) . '_all]';
+        } else {
+            $name .= '_all';
+        }
+
+        return $name;
+    }
+
+    /**
+     * Registers the needed JavaScript
+     * @since 2.0.8
+     */
+    public function registerClientScript()
+    {
+        $id = $this->grid->options['id'];
+        $options = Json::encode([
+            'name' => $this->name,
+            'multiple' => $this->multiple,
+            'checkAll' => $this->grid->showHeader ? $this->getHeaderCheckBoxName() : null,
+        ]);
+        $this->grid->getView()->registerJs("jQuery('#$id').yiiGridView('setSelectionColumn', $options);");
     }
 }
diff --git a/framework/grid/GridView.php b/framework/grid/GridView.php
index edea8f7..b2bca6c 100644
--- a/framework/grid/GridView.php
+++ b/framework/grid/GridView.php
@@ -272,11 +272,6 @@ class GridView extends BaseListView
             $this->filterRowOptions['id'] = $this->options['id'] . '-filters';
         }
 
-        $id = $this->options['id'];
-        $options = Json::htmlEncode($this->getClientOptions());
-        $view = $this->getView();
-        $view->registerJs("jQuery('#$id').yiiGridView($options);");
-
         $this->initColumns();
     }
 
@@ -285,9 +280,11 @@ class GridView extends BaseListView
      */
     public function run()
     {
+        $id = $this->options['id'];
+        $options = Json::htmlEncode($this->getClientOptions());
         $view = $this->getView();
         GridViewAsset::register($view);
-
+        $view->registerJs("jQuery('#$id').yiiGridView($options);");
         parent::run();
     }