diff --git a/src/wp-includes/blocks.php b/src/wp-includes/blocks.php
index ace9811f32e1b..9cfbfdb5dcaec 100644
--- a/src/wp-includes/blocks.php
+++ b/src/wp-includes/blocks.php
@@ -169,12 +169,17 @@ function register_block_style_handle( $metadata, $field_name ) {
 
 	$style_handle = generate_block_asset_handle( $metadata['name'], $field_name );
 	$block_dir    = dirname( $metadata['file'] );
+	$style_file   = realpath( "$block_dir/$style_path" );
 	$result       = wp_register_style(
 		$style_handle,
 		plugins_url( $style_path, $metadata['file'] ),
 		array(),
-		filemtime( realpath( "$block_dir/$style_path" ) )
+		filemtime( $style_file )
 	);
+	if ( file_exists( str_replace( '.css', '-rtl.css', $style_file ) ) ) {
+		wp_style_add_data( $style_handle, 'rtl', 'replace' );
+	}
+
 	return $result ? $style_handle : false;
 }
 
diff --git a/tests/phpunit/data/blocks/notice/block-rtl.css b/tests/phpunit/data/blocks/notice/block-rtl.css
new file mode 100644
index 0000000000000..2572f27aaf2d9
--- /dev/null
+++ b/tests/phpunit/data/blocks/notice/block-rtl.css
@@ -0,0 +1 @@
+/* Test CSS file - RTL version */
diff --git a/tests/phpunit/tests/blocks/register.php b/tests/phpunit/tests/blocks/register.php
index 5ea58af398acc..1d6e845d6f7c2 100644
--- a/tests/phpunit/tests/blocks/register.php
+++ b/tests/phpunit/tests/blocks/register.php
@@ -269,6 +269,7 @@ function test_success_register_block_style_handle() {
 		$result   = register_block_style_handle( $metadata, 'style' );
 
 		$this->assertSame( 'unit-tests-test-block-style', $result );
+		$this->assertSame( 'replace', wp_styles()->get_data( 'unit-tests-test-block-style', 'rtl' ) );
 	}
 
 	/**