diff --git a/src/wp-includes/widgets/class-wp-widget-tag-cloud.php b/src/wp-includes/widgets/class-wp-widget-tag-cloud.php
index c23cda21f1..8b5c4a80b9 100644
--- a/src/wp-includes/widgets/class-wp-widget-tag-cloud.php
+++ b/src/wp-includes/widgets/class-wp-widget-tag-cloud.php
@@ -90,11 +90,28 @@ class WP_Widget_Tag_Cloud extends WP_Widget {
 			echo $args['before_title'] . $title . $args['after_title'];
 		}
 
+		$format = current_theme_supports( 'html5', 'navigation-widgets' ) ? 'html5' : 'xhtml';
+
+		/** This filter is documented in wp-includes/widgets/class-wp-nav-menu-widget.php */
+		$format = apply_filters( 'navigation_widgets_format', $format );
+
+		if ( 'html5' === $format ) {
+			// The title may be filtered: Strip out HTML and make sure the aria-label is never empty.
+			$title      = trim( strip_tags( $title ) );
+			$aria_label = $title ? $title : $default_title;
+			echo '<nav role="navigation" aria-label="' . esc_attr( $aria_label ) . '">';
+		}
+
 		echo '<div class="tagcloud">';
 
 		echo $tag_cloud;
 
 		echo "</div>\n";
+
+		if ( 'html5' === $format ) {
+			echo '</nav>';
+		}
+
 		echo $args['after_widget'];
 	}