Index: src/wp-includes/kses.php
===================================================================
--- src/wp-includes/kses.php	(revision 35863)
+++ src/wp-includes/kses.php	(working copy)
@@ -398,6 +398,7 @@
 		'ol' => array(
 			'start' => true,
 			'type' => true,
+			'reversed' => true,
 		),
 		'var' => array(),
 		'video' => array(
Index: tests/phpunit/tests/kses.php
===================================================================
--- tests/phpunit/tests/kses.php	(revision 35863)
+++ tests/phpunit/tests/kses.php	(working copy)
@@ -653,4 +653,15 @@
 
 		$this->assertEquals( $input, wp_kses( $input, $allowedposttags ) );
 	}
+
+	/**
+	 * @ticket 35079
+	 */
+	function test_ol_reversed() {
+		global $allowedposttags;
+
+		$input = '<ol reversed="reversed"><li>Item 1</li><li>Item 2</li><li>Item 3</li></ol>';
+
+		$this->assertEquals( $input, wp_kses( $input, $allowedposttags ) );
+	}
 }