diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index ebcefd9..e6e3546 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -17,6 +17,7 @@ Yii Framework 2 Change Log
 - Enh #18493: Faster request parsing for REST UrlRule with prefix handling (bizley)
 - Enh #18487: Allow creating URLs for non-GET-verb rules (bizley)
 - Bug #8750: Fix MySQL support when running in `ANSI`/`ANSI_QUOTES` modes (brandonkelly)
+- Bug #18505: Fixed `yii\helpers\ArrayHelper::getValue()` for ArrayAccess objects with explicitly defined properties (samdark)
 
 
 2.0.40 December 23, 2020
diff --git a/framework/helpers/BaseArrayHelper.php b/framework/helpers/BaseArrayHelper.php
index 6e7d645..8bc7ef2 100644
--- a/framework/helpers/BaseArrayHelper.php
+++ b/framework/helpers/BaseArrayHelper.php
@@ -196,6 +196,10 @@ class BaseArrayHelper
             $key = $lastKey;
         }
 
+        if (is_object($array) && property_exists($array, $key)) {
+            return $array->$key;
+        }
+
         if (static::keyExists($key, $array)) {
             return $array[$key];
         }
diff --git a/tests/framework/helpers/ArrayHelperTest.php b/tests/framework/helpers/ArrayHelperTest.php
index a5f8aae..fae9d02 100644
--- a/tests/framework/helpers/ArrayHelperTest.php
+++ b/tests/framework/helpers/ArrayHelperTest.php
@@ -10,6 +10,7 @@ namespace yiiunit\framework\helpers;
 use ArrayAccess;
 use Iterator;
 use yii\base\BaseObject;
+use yii\base\Model;
 use yii\data\Sort;
 use yii\helpers\ArrayHelper;
 use yiiunit\TestCase;
@@ -122,6 +123,23 @@ class TraversableArrayAccessibleObject extends ArrayAccessibleObject implements
     }
 }
 
+class MagicModel extends Model
+{
+    protected $magic;
+
+    public function getMagic()
+    {
+        return 42;
+    }
+
+    private $moreMagic;
+
+    public function getMoreMagic()
+    {
+        return 'ta-da';
+    }
+}
+
 /**
  * @group helpers
  */
@@ -1536,4 +1554,15 @@ class ArrayHelperTest extends TestCase
         $this->assertEquals(123, ArrayHelper::getValue($data, 'value'));
         $this->assertEquals('bar1', ArrayHelper::getValue($data, 'name'));
     }
+
+    /**
+     * https://github.com/yiisoft/yii2/commit/35fb9c624893855317e5fe52e6a21f6518a9a31c changed the way
+     * ArrayHelper works with existing object properties in case of ArrayAccess.
+     */
+    public function testArrayAccessWithMagicProperty()
+    {
+        $model = new MagicModel();
+        $this->assertEquals(42, ArrayHelper::getValue($model, 'magic'));
+        $this->assertEquals('ta-da', ArrayHelper::getValue($model, 'moreMagic'));
+    }
 }