diff --git a/_inc/client/traffic/related-posts.jsx b/_inc/client/traffic/related-posts.jsx
index 925f2d1e8f64c..f33671379ea88 100644
--- a/_inc/client/traffic/related-posts.jsx
+++ b/_inc/client/traffic/related-posts.jsx
@@ -66,6 +66,9 @@ class RelatedPostsComponent extends React.Component {
 						link: 'https://jetpack.com/support/related-posts/',
 					} }
 				>
+					<p className="jp-form-setting-explanation">
+						{ __( 'The following settings will impact all related posts on your site, except for those you created via the block editor:' ) }
+					</p>
 					<ModuleToggle
 						slug="related-posts"
 						disabled={ unavailableInDevMode }
diff --git a/modules/related-posts/class.related-posts-customize.php b/modules/related-posts/class.related-posts-customize.php
index 8349b530043c4..f685395105f6e 100644
--- a/modules/related-posts/class.related-posts-customize.php
+++ b/modules/related-posts/class.related-posts-customize.php
@@ -95,7 +95,7 @@ function customize_register( $wp_customize ) {
 		// If selective refresh is available, implement it.
 		if ( isset( $wp_customize->selective_refresh ) ) {
 			$wp_customize->selective_refresh->add_partial( "$this->prefix", array(
-				'selector'            => '.jp-relatedposts',
+				'selector'            => '.jp-relatedposts:not(.jp-relatedposts-block)',
 				'settings'            => $selective_options,
 				'render_callback'     => __CLASS__ . '::render_callback',
 				'container_inclusive' => false,
@@ -113,25 +113,56 @@ public static function render_callback() {
 		echo Jetpack_RelatedPosts::init()->get_headline();
 	}
 
+	/**
+	 * Check whether the current post contains a Related Posts block.
+	 * If we're on WP < 5.0, this automatically means it doesn't,
+	 * because block support is intrododuced in WP 5.0.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @return bool
+	 */
+	public static function contains_related_posts_block() {
+		if ( ! function_exists( 'has_block' ) ) {
+			return false;
+		}
+
+		if ( has_block( 'jetpack/related-posts' ) ) {
+			return true;
+		}
+
+		return false;
+	}
+
 	/**
 	 * Check that we're in a single post view.
+	 * Will return `false` if the current post contains a Related Posts block,
+	 * because in that case we want to hide the Customizer controls.
 	 *
 	 * @since 4.4.0
 	 *
 	 * @return bool
 	 */
 	public static function is_single() {
+		if ( self::contains_related_posts_block() ) {
+			return false;
+		}
 		return is_single();
 	}
 
 	/**
 	 * Check that we're not in a single post view.
+	 * Will return `false` if the current post contains a Related Posts block,
+	 * because in that case we want to hide the Customizer controls.
 	 *
 	 * @since 4.4.0
 	 *
 	 * @return bool
 	 */
 	public static function is_not_single() {
+		if ( self::contains_related_posts_block() ) {
+			return false;
+		}
 		return ! is_single();
 	}
 
diff --git a/modules/related-posts/jetpack-related-posts.php b/modules/related-posts/jetpack-related-posts.php
index fcbe23e771f0b..7ae8a1e0de11e 100644
--- a/modules/related-posts/jetpack-related-posts.php
+++ b/modules/related-posts/jetpack-related-posts.php
@@ -1,6 +1,6 @@
 <?php
 class Jetpack_RelatedPosts {
-	const VERSION = '20150408';
+	const VERSION = '20181213';
 	const SHORTCODE = 'jetpack-related-posts';
 	private static $instance = null;
 	private static $instance_raw = null;
@@ -77,10 +77,15 @@ public function __construct( $blog_id_local, $blog_id_wpcom ) {
 
 		// Add Related Posts to the REST API Post response.
 		if ( function_exists( 'register_rest_field' ) ) {
-			add_action( 'rest_api_init',  array( $this, 'rest_register_related_posts' ) );
+			add_action( 'rest_api_init', array( $this, 'rest_register_related_posts' ) );
 		}
 
-		jetpack_register_block( 'related-posts' );
+		jetpack_register_block(
+			'related-posts',
+			array(
+				'render_callback' => array( $this, 'render_block' ),
+			)
+		);
 	}
 
 	/**
@@ -125,17 +130,7 @@ public function action_frontend_init() {
 			return;
 
 		if ( isset( $_GET['relatedposts'] ) ) {
-			$excludes = array();
-			if ( isset( $_GET['relatedposts_exclude'] ) ) {
-				if ( is_string( $_GET['relatedposts_exclude'] ) ) {
-					$excludes = explode( ',', $_GET['relatedposts_exclude'] );
-				} elseif ( is_array( $_GET['relatedposts_exclude'] ) ) {
-					$excludes = array_values( $_GET['relatedposts_exclude'] );
-				}
-
-				$excludes = array_unique( array_filter( array_map( 'absint', $excludes ) ) );
-			}
-
+			$excludes = $this->parse_numeric_get_arg( 'relatedposts_exclude' );
 			$this->_action_frontend_init_ajax( $excludes );
 		} else {
 			if ( isset( $_GET['relatedposts_hit'], $_GET['relatedposts_origin'], $_GET['relatedposts_position'] ) ) {
@@ -172,13 +167,18 @@ public function get_headline() {
 
 	/**
 	 * Adds a target to the post content to load related posts into if a shortcode for it did not already exist.
+	 * Will skip adding the target if the post content contains a Related Posts block.
 	 *
 	 * @filter the_content
 	 * @param string $content
 	 * @returns string
 	 */
 	public function filter_add_target_to_dom( $content ) {
-		if ( !$this->_found_shortcode ) {
+		if ( function_exists( 'has_block' ) && has_block( 'jetpack/related-posts', $content ) ) {
+			return $content;
+		}
+
+		if ( ! $this->_found_shortcode ) {
 			$content .= "\n" . $this->get_target_html();
 		}
 
@@ -248,12 +248,147 @@ public function get_target_html_unsupported() {
 		return "\n\n<!-- Jetpack Related Posts is not supported in this context. -->\n\n";
 	}
 
+	/**
+	 * ===============
+	 * GUTENBERG BLOCK
+	 * ===============
+	 */
+
+	/**
+	 * Render the related posts markup.
+	 *
+	 * @param array $attributes Block attributes.
+	 * @return string
+	 */
+	public function render_block( $attributes ) {
+		$block_attributes = array(
+			'show_thumbnails' => isset( $attributes['displayThumbnails'] ) && $attributes['displayThumbnails'],
+			'show_date'       => isset( $attributes['displayDate'] ) ? (bool) $attributes['displayDate'] : true,
+			'show_context'    => isset( $attributes['displayContext'] ) && $attributes['displayContext'],
+			'layout'          => isset( $attributes['postLayout'] ) && 'list' === $attributes['postLayout'] ? $attributes['postLayout'] : 'grid',
+			'size'            => ! empty( $attributes['postsToShow'] ) ? absint( $attributes['postsToShow'] ) : 3,
+		);
+
+		$excludes = $this->parse_numeric_get_arg( 'relatedposts_origin' );
+		$related_posts = $this->get_for_post_id(
+			get_the_ID(),
+			array(
+				'size'             => $block_attributes['size'],
+				'exclude_post_ids' => $excludes,
+			)
+		);
+
+		if ( ! $related_posts ) {
+			return '';
+		}
+
+		ob_start();
+		?>
+		<div id="jp-relatedposts" class="jp-relatedposts jp-relatedposts-block" style="display: block;">
+			<div class="jp-relatedposts-items <?php echo $block_attributes['show_thumbnails'] ? 'jp-relatedposts-items-visual ' : ''; ?>jp-relatedposts-<?php echo esc_attr( $block_attributes['layout'] ); ?>">
+				<?php
+				foreach ( $related_posts as $index => $related_post ) :
+					$classes = array_filter(
+						array(
+							'jp-relatedposts-post',
+							'jp-relatedposts-post' . $index,
+							! empty( $block_attributes['show_thumbnails'] ) ? 'jp-relatedposts-post-thumbs' : '',
+						)
+					);
+					$title_attr = $related_post['title'];
+					if ( '' !== $related_post['excerpt'] ) {
+						$title_attr .= "\n\n" . $related_post['excerpt'];
+					}
+					?>
+					<div
+						class="<?php echo esc_attr( implode( ' ', $classes ) ); ?>"
+						data-post-id="<?php echo esc_attr( $related_post['id'] ); ?>"
+						data-post-format="<?php echo esc_attr( ! empty( $related_post['format'] ) ? $related_post['format'] : 'false' ); ?>"
+					>
+						<?php if ( ! empty( $block_attributes['show_thumbnails'] ) && ! empty( $related_post['img']['src'] ) ) : ?>
+							<a class="jp-relatedposts-post-a"
+								href="<?php echo esc_url( $related_post['url'] ); ?>"
+								title="<?php echo esc_attr( $title_attr ); ?>"
+								rel="<?php echo esc_attr( $related_post['rel'] ); ?>"
+								data-origin="<?php echo esc_attr( $related_post['url_meta']['origin'] ); ?>"
+								data-position="<?php echo esc_attr( $related_post['url_meta']['position'] ); ?>"
+							>
+								<img class="jp-relatedposts-post-img"
+									src="<?php echo esc_url( $related_post['img']['src'] ); ?>"
+									width="<?php echo esc_attr( $related_post['img']['width'] ); ?>"
+									alt="<?php echo esc_attr( $title_attr ); ?>"
+								/>
+							</a>
+						<?php endif; ?>
+
+						<h4 class="jp-relatedposts-post-title">
+							<a
+								class="jp-relatedposts-post-a"
+								href="<?php echo esc_url( $related_post['url'] ); ?>"
+								title="<?php echo esc_attr( $title_attr ); ?>"
+								rel="<?php echo esc_attr( $related_post['rel'] ); ?>"
+								data-origin="<?php echo esc_attr( $related_post['url_meta']['origin'] ); ?>"
+								data-position="<?php echo esc_attr( $related_post['url_meta']['position'] ); ?>"
+							>
+								<?php echo esc_html( $related_post['title'] ); ?>
+							</a>
+						</h4>
+
+						<p class="jp-relatedposts-post-excerpt"><?php echo esc_html( $related_post['excerpt'] ); ?></p>
+
+						<?php if ( $block_attributes['show_date'] ) : ?>
+							<p class="jp-relatedposts-post-date" style="display: block;">
+								<?php echo esc_html( $related_post['date'] ); ?>
+							</p>
+						<?php endif; ?>
+
+						<?php if ( $block_attributes['show_context'] ) : ?>
+							<p class="jp-relatedposts-post-context">
+								<?php echo esc_html( $related_post['context'] ); ?>
+							</p>
+						<?php endif; ?>
+					</div>
+				<?php endforeach; ?>
+			</div>
+		</div>
+		<?php
+		$html = ob_get_clean();
+
+		return $html;
+	}
+
 	/**
 	 * ========================
 	 * PUBLIC UTILITY FUNCTIONS
 	 * ========================
 	 */
 
+	/**
+	 * Parse a numeric GET variable to an array of values.
+	 *
+	 * @since 6.9.0
+	 *
+	 * @uses absint
+	 *
+	 * @param string $arg Name of the GET variable
+	 * @return array $result Parsed value(s)
+	 */
+	public function parse_numeric_get_arg( $arg ) {
+		$result = array();
+
+		if ( isset( $_GET[ $arg ] ) ) {
+			if ( is_string( $_GET[ $arg ] ) ) {
+				$result = explode( ',', $_GET[ $arg ] );
+			} elseif ( is_array( $_GET[ $arg ] ) ) {
+				$result = array_values( $_GET[ $arg ] );
+			}
+
+			$result = array_unique( array_filter( array_map( 'absint', $result ) ) );
+		}
+
+		return $result;
+	}
+
 	/**
 	 * Gets options set for Jetpack_RelatedPosts and merge with defaults.
 	 *
@@ -364,6 +499,7 @@ public function print_setting_html() {
 		$options = $this->get_options();
 
 		$ui_settings_template = <<<EOT
+<p class="description">%s</p>
 <ul id="settings-reading-relatedposts-customize">
 	<li>
 		<label><input name="jetpack_relatedposts[show_headline]" type="checkbox" value="1" %s /> %s</label>
@@ -385,6 +521,7 @@ public function print_setting_html() {
 EOT;
 		$ui_settings = sprintf(
 			$ui_settings_template,
+			esc_html__( 'The following settings will impact all related posts on your site, except for those you created via the block editor:', 'jetpack' ),
 			checked( $options['show_headline'], true, false ),
 			esc_html__( 'Highlight related content with a heading', 'jetpack' ),
 			checked( $options['show_thumbnails'], true, false ),
diff --git a/modules/related-posts/related-posts.js b/modules/related-posts/related-posts.js
index ac2eb0d4f1ed4..c3cc1c53e1197 100644
--- a/modules/related-posts/related-posts.js
+++ b/modules/related-posts/related-posts.js
@@ -194,6 +194,13 @@
 		}
 	};
 
+	function afterPostsHaveLoaded() {
+		jprp.setVisualExcerptHeights();
+		$( '#jp-relatedposts a.jp-relatedposts-post-a' ).click( function() {
+			this.href = jprp.getTrackedUrl( this );
+		} );
+	}
+
 	/**
 	 * Initialize Related Posts.
 	 */
@@ -203,6 +210,11 @@
 		var endpointURL = jprp.getEndpointURL(),
 			$relatedPosts = $( '#jp-relatedposts' );
 
+		if ( $( '#jp-relatedposts .jp-relatedposts-post' ).length ) {
+			afterPostsHaveLoaded();
+			return;
+		}
+
 		$.getJSON( endpointURL, function( response ) {
 			if ( 0 === response.items.length || 0 === $relatedPosts.length ) {
 				return;
@@ -229,15 +241,11 @@
 			html = ! showThumbnails ? jprp.generateMinimalHtml( response.items, options ) : jprp.generateVisualHtml( response.items, options );
 
 			$relatedPosts.append( html );
-			jprp.setVisualExcerptHeights();
 			if ( options.showDate ) {
 				$relatedPosts.find( '.jp-relatedposts-post-date' ).show();
 			}
 			$relatedPosts.show();
-
-			$( '#jp-relatedposts a.jp-relatedposts-post-a' ).click(function() {
-				this.href = jprp.getTrackedUrl( this );
-			});
+			afterPostsHaveLoaded();
 		} );
 	}