diff --git a/src/wp-includes/kses.php b/src/wp-includes/kses.php
index 9504f48679..d34608b89f 100644
--- a/src/wp-includes/kses.php
+++ b/src/wp-includes/kses.php
@@ -97,6 +97,9 @@ if ( ! CUSTOM_TAGS ) {
 			'src' => true,
 		),
 		'b' => array(),
+		'bdo' => array(
+			'dir' => true,
+		),
 		'big' => array(),
 		'blockquote' => array(
 			'cite' => true,
diff --git a/tests/phpunit/tests/kses.php b/tests/phpunit/tests/kses.php
index 5c053513be..c4c1e8e24c 100644
--- a/tests/phpunit/tests/kses.php
+++ b/tests/phpunit/tests/kses.php
@@ -374,7 +374,7 @@ EOF;
 		$this->assertEquals( '¾', wp_kses_normalize_entities( '¾' ) );
 		$this->assertEquals( '∴', wp_kses_normalize_entities( '∴' ) );
 	}
-	
+
 	/**
 	 * Test removal of invalid binary data for HTML.
 	 *
@@ -411,7 +411,7 @@ EOF;
 			),
 		);
 	}
-	
+
 	/**
 	 * Test removal of '\0' strings.
 	 *
@@ -423,7 +423,7 @@ EOF;
 
 		return $this->assertEquals( $output, wp_kses( $input, $allowedposttags ) );
 	}
-	
+
 	function data_slash_zero_removal() {
 		return array(
 			array(
@@ -642,4 +642,15 @@ EOF;
 			),
 		);
 	}
+
+	/**
+	 * @ticket 34063
+	 */
+	function test_bdo() {
+		global $allowedposttags;
+
+		$input = '<p>This is <bdo dir="rtl">a BDO tag</bdo>. Weird, <bdo dir="ltr">right?</bdo></p>';
+
+		$this->assertEquals( $input, wp_kses( $input, $allowedposttags ) );
+	}
 }