diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index a64e346697..89b7935da7 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -4,6 +4,7 @@ Yii Framework 2 Change Log
 2.0.16 under development
 ------------------------
 
+- Bug #16022: Fix UniqueValidator for PostgreSQL. Checks the uniqueness of keys in `jsonb` field (lav45)
 - Bug #16903: Fixed 'yii\validators\NumberValidator' method 'isNotNumber' returns false for true/false value (annechko)
 - Bug #16648: Html::strtolower() was corrupting UTF-8 strings (Kolyunya)
 - Bug #13977: Skip validation if file input does not exist (RobinKamps, s1lver)
diff --git a/framework/validators/UniqueValidator.php b/framework/validators/UniqueValidator.php
index 3f7a6fa075..5634f93652 100644
--- a/framework/validators/UniqueValidator.php
+++ b/framework/validators/UniqueValidator.php
@@ -178,7 +178,7 @@ class UniqueValidator extends Validator
      */
     private function modelExists($targetClass, $conditions, $model)
     {
-        /** @var ActiveRecordInterface $targetClass $query */
+        /** @var ActiveRecordInterface|\yii\base\BaseObject $targetClass $query */
         $query = $this->prepareQuery($targetClass, $conditions);
 
         if (!$model instanceof ActiveRecordInterface || $model->getIsNewRecord() || $model->className() !== $targetClass::className()) {
@@ -311,10 +311,12 @@ class UniqueValidator extends Validator
         $prefixedConditions = [];
         foreach ($conditions as $columnName => $columnValue) {
             if (strpos($columnName, '(') === false) {
-                $prefixedColumn = "{$alias}.[[" . preg_replace(
-                    '/^' . preg_quote($alias) . '\.(.*)$/',
-                    '$1',
-                    $columnName) . ']]';
+                $columnName = preg_replace('/^' . preg_quote($alias) . '\.(.*)$/', '$1', $columnName);
+                if (strpos($columnName, '[[') === 0) {
+                    $prefixedColumn = "{$alias}.{$columnName}";
+                } else {
+                    $prefixedColumn = "{$alias}.[[{$columnName}]]";
+                }
             } else {
                 // there is an expression, can't prefix it reliably
                 $prefixedColumn = $columnName;
diff --git a/tests/data/ar/Type.php b/tests/data/ar/Type.php
index c57db8ae24..68d855720e 100644
--- a/tests/data/ar/Type.php
+++ b/tests/data/ar/Type.php
@@ -26,6 +26,8 @@ namespace yiiunit\data\ar;
  */
 class Type extends ActiveRecord
 {
+    public $name;
+
     /**
      * {@inheritdoc}
      */
diff --git a/tests/framework/db/pgsql/UniqueValidatorTest.php b/tests/framework/db/pgsql/UniqueValidatorTest.php
index d31a535eef..754297b032 100644
--- a/tests/framework/db/pgsql/UniqueValidatorTest.php
+++ b/tests/framework/db/pgsql/UniqueValidatorTest.php
@@ -7,6 +7,9 @@
 
 namespace yiiunit\framework\db\pgsql;
 
+use yii\validators\UniqueValidator;
+use yiiunit\data\ar\Type;
+
 /**
  * @group db
  * @group pgsql
@@ -15,4 +18,19 @@ namespace yiiunit\framework\db\pgsql;
 class UniqueValidatorTest extends \yiiunit\framework\validators\UniqueValidatorTest
 {
     public $driverName = 'pgsql';
+
+    public function testPrepareParams()
+    {
+        parent::testPrepareParams();
+
+        // Add table prefix for column name
+        $model = new Type;
+        $model->name = 'Angela';
+
+        $attribute = 'name';
+        $targetAttribute = [$attribute => "[[jsonb_col]]->>'name'"];
+        $result = $this->invokeMethod(new UniqueValidator(), 'prepareConditions', [$targetAttribute, $model, $attribute]);
+        $expected = ['{{' . Type::tableName() . '}}.' . $targetAttribute[$attribute]  => $model->name];
+        $this->assertEquals($expected, $result);
+    }
 }