diff --git a/amp.php b/amp.php
index 8e8558f888a..07694de2fef 100644
--- a/amp.php
+++ b/amp.php
@@ -88,6 +88,7 @@ function amp_after_setup_theme() {
 	}
 
 	add_action( 'init', 'amp_init' );
+	add_action( 'rest_api_init', 'amp_rest_init' );
 	add_action( 'widgets_init', 'AMP_Theme_Support::register_widgets' );
 	add_action( 'admin_init', 'AMP_Options_Manager::register_settings' );
 	add_filter( 'amp_post_template_analytics', 'amp_add_custom_analytics' );
@@ -125,6 +126,18 @@ function amp_init() {
 	if ( class_exists( 'Jetpack' ) && ! ( defined( 'IS_WPCOM' ) && IS_WPCOM ) ) {
 		require_once( AMP__DIR__ . '/jetpack-helper.php' );
 	}
+
+	amp_hook_comments_maybe();
+}
+
+/**
+ * Init AMP Rest endpoints.
+ *
+ * @since 0.1
+ */
+function amp_rest_init() {
+	require_once AMP__DIR__ . '/includes/amp-rest-functions.php';
+	amp_register_endpoints();
 }
 
 // Make sure the `amp` query var has an explicit value.
@@ -361,3 +374,64 @@ function amp_redirect_old_slug_to_new_url( $link ) {
 
 	return $link;
 }
+
+/**
+ * Hook into a comment submission if an AMP xhr post request.
+ */
+function amp_hook_comments_maybe() {
+
+	$method        = filter_input( INPUT_SERVER, 'REQUEST_METHOD', FILTER_SANITIZE_STRING );
+	$is_amp_submit = filter_input( INPUT_GET, '__amp_source_origin', FILTER_VALIDATE_URL );
+
+	if ( 'post' !== strtolower( $method ) || is_null( $is_amp_submit ) ) {
+		return;
+	}
+
+	// Add amp comment hooks.
+	add_filter( 'comment_post_redirect', 'amp_comment_post_redirect', PHP_INT_MAX, 2 );
+	add_filter( 'wp_die_handler', 'amp_set_comment_submit_die_handler' );
+
+	// Send amp header.
+	header( 'AMP-Access-Control-Allow-Source-Origin: ' . $is_amp_submit, true );
+
+}
+
+/**
+ * Set the die handler on comment submit to output the error in json and send AMP headers.
+ */
+function amp_set_comment_submit_die_handler() {
+	return 'amp_send_error_json';
+}
+
+/**
+ * Send error creating message.
+ *
+ * @param string $message The error message to send.
+ */
+function amp_send_error_json( $message ) {
+	header( 'HTTP/1.1 400 BAD REQUEST' );
+	wp_send_json( array( 'error' => strip_tags( $message, 'strong' ) ) );
+}
+
+/**
+ * Redirect after comment submission.
+ *
+ * @param string     $location The location to redirect to.
+ * @param WP_Comment $comment The comment that was posted.
+ * @return string The location URL or void if send json.
+ */
+function amp_comment_post_redirect( $location, $comment ) {
+	$is_amp_submit = filter_input( INPUT_GET, '__amp_source_origin', FILTER_VALIDATE_URL );
+	if ( is_null( $is_amp_submit ) ) {
+		return $location;
+	}
+
+	// AMP-Redirect only works if https. If not, we simply render the success.
+	if ( is_ssl() ) {
+		$location = strtok( $location, '#' );
+		header( 'AMP-Redirect-To: ' . $location );
+		header( 'Access-Control-Expose-Headers: AMP-Redirect-To', false );
+	}
+	$comment->comment_link = get_comment_link( $comment->comment_ID );
+	wp_send_json( $comment );
+}
diff --git a/includes/amp-helper-functions.php b/includes/amp-helper-functions.php
index 70b9fa42f03..7efcd0adc3e 100644
--- a/includes/amp-helper-functions.php
+++ b/includes/amp-helper-functions.php
@@ -222,6 +222,8 @@ function amp_get_content_sanitizers( $post = null ) {
 			'AMP_Video_Sanitizer'             => array(),
 			'AMP_Audio_Sanitizer'             => array(),
 			'AMP_Playbuzz_Sanitizer'          => array(),
+			'AMP_Form_Sanitizer'              => array(),
+			'AMP_Comments_Sanitizer'          => array(),
 			'AMP_Iframe_Sanitizer'            => array(
 				'add_placeholder' => true,
 			),
diff --git a/includes/amp-rest-functions.php b/includes/amp-rest-functions.php
new file mode 100644
index 00000000000..a8dc38819a5
--- /dev/null
+++ b/includes/amp-rest-functions.php
@@ -0,0 +1,71 @@
+<?php
+/**
+ * AMP Rest Functions
+ *
+ * @package AMP
+ */
+
+/**
+ * Register the comments REST endpoint.
+ *
+ * @since 0.7
+ */
+function amp_register_endpoints() {
+
+	register_rest_route( 'amp/v1', '/comments/(?P<id>\d+)', array(
+		'methods'  => 'GET',
+		'callback' => 'amp_get_comments',
+	) );
+
+}
+
+/**
+ * Get comments for the Post and Parent
+ *
+ * @since 0.7
+ * @param WP_REST_Request $request The REST request.
+ *
+ * @return array The array of comments.
+ */
+function amp_get_comments( $request ) {
+
+	$id       = $request->get_param( 'id' );
+	$comments = get_comments( array(
+		'post_ID' => $id,
+		'order'   => 'ASC',
+	) );
+	$return   = array(
+		'items' => array(
+			'comment' => amp_get_comments_recursive( 0, $comments ),
+		),
+	);
+
+	return $return;
+}
+
+/**
+ * Recursively get comments for the Post and Parent
+ *
+ * @since 0.7
+ * @param int   $parent The comment parent.
+ * @param array $comments The list of comments.
+ *
+ * @return array The array of comments.
+ */
+function amp_get_comments_recursive( $parent, $comments ) {
+
+	$return = array();
+	foreach ( $comments as $comment ) {
+		if ( (int) $parent !== (int) $comment->comment_parent ) {
+			continue;
+		}
+		$GLOBALS['comment']          = $comment; // WPCS: override ok.
+		$comment->comment_date       = get_comment_date();
+		$comment->comment_time       = get_comment_time();
+		$comment->comment_avatar_url = get_avatar_url( $comment->comment_author_email );
+		$comment->comment            = amp_get_comments_recursive( $comment->comment_ID, $comments );
+		$return[]                    = $comment;
+	}
+
+	return $return;
+}
diff --git a/includes/class-amp-autoloader.php b/includes/class-amp-autoloader.php
index 37264085486..adaa5e1015b 100644
--- a/includes/class-amp-autoloader.php
+++ b/includes/class-amp-autoloader.php
@@ -30,6 +30,7 @@ class AMP_Autoloader {
 	 */
 	private static $_classmap = array(
 		'AMP_Theme_Support'                           => 'includes/class-amp-theme-support',
+		'AMP_Comment_Walker'                          => 'includes/class-amp-comment-walker',
 		'AMP_WP_Styles'                               => 'includes/class-amp-wp-styles',
 		'AMP_Template_Customizer'                     => 'includes/admin/class-amp-customizer',
 		'AMP_Post_Meta_Box'                           => 'includes/admin/class-amp-post-meta-box',
@@ -65,6 +66,8 @@ class AMP_Autoloader {
 		'AMP_Blacklist_Sanitizer'                     => 'includes/sanitizers/class-amp-blacklist-sanitizer',
 		'AMP_Iframe_Sanitizer'                        => 'includes/sanitizers/class-amp-iframe-sanitizer',
 		'AMP_Img_Sanitizer'                           => 'includes/sanitizers/class-amp-img-sanitizer',
+		'AMP_Form_Sanitizer'                          => 'includes/sanitizers/class-amp-form-sanitizer',
+		'AMP_Comments_Sanitizer'                      => 'includes/sanitizers/class-amp-comments-sanitizer',
 		'AMP_Playbuzz_Sanitizer'                      => 'includes/sanitizers/class-amp-playbuzz-sanitizer',
 		'AMP_Style_Sanitizer'                         => 'includes/sanitizers/class-amp-style-sanitizer',
 		'AMP_Tag_And_Attribute_Sanitizer'             => 'includes/sanitizers/class-amp-tag-and-attribute-sanitizer',
diff --git a/includes/class-amp-comment-walker.php b/includes/class-amp-comment-walker.php
new file mode 100644
index 00000000000..9b01bd08023
--- /dev/null
+++ b/includes/class-amp-comment-walker.php
@@ -0,0 +1,105 @@
+<?php
+/**
+ * Class AMP_Comment_Walker
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Comment_Walker
+ *
+ * Walker to wrap comments in mustache tags for amp-template.
+ */
+class AMP_Comment_Walker extends Walker_Comment {
+
+	/**
+	 * The original comments arguments.
+	 *
+	 * @since 0.7
+	 * @var array
+	 */
+	public $args;
+
+	/**
+	 * Starts the element output.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @see Walker::start_el()
+	 * @see wp_list_comments()
+	 * @global int        $comment_depth
+	 * @global WP_Comment $comment
+	 *
+	 * @param string     $output  Used to append additional content. Passed by reference.
+	 * @param WP_Comment $comment Comment data object.
+	 * @param int        $depth   Optional. Depth of the current comment in reference to parents. Default 0.
+	 * @param array      $args    Optional. An array of arguments. Default empty array.
+	 * @param int        $id      Optional. ID of the current comment. Default 0 (unused).
+	 */
+	public function start_el( &$output, $comment, $depth = 0, $args = array(), $id = 0 ) {
+		$output .= '{{#comment}}';
+		parent::start_el( $output, $comment, $depth, $args, $id );
+	}
+	/**
+	 * Ends the element output, if needed.
+	 *
+	 * @since 2.7.0
+	 *
+	 * @see Walker::end_el()
+	 * @see wp_list_comments()
+	 *
+	 * @param string     $output  Used to append additional content. Passed by reference.
+	 * @param WP_Comment $comment The current comment object. Default current comment.
+	 * @param int        $depth   Optional. Depth of the current comment. Default 0.
+	 * @param array      $args    Optional. An array of arguments. Default empty array.
+	 */
+	public function end_el( &$output, $comment, $depth = 0, $args = array() ) {
+		if ( ! empty( $args['end-callback'] ) ) {
+			ob_start();
+			call_user_func( $args['end-callback'], $comment, $args, $depth );
+			$output .= ob_get_clean();
+		} else {
+			if ( 'div' === $args['style'] ) {
+				$output .= "</div><!-- #comment-## -->\n";
+			} else {
+				$output .= "</li><!-- #comment-## -->\n";
+			}
+		}
+		$output .= '{{/comment}}';
+	}
+
+	/**
+	 * Output amp-list template code and place holder for comments.
+	 *
+	 * @see Walker::paged_walk()
+	 * @param array $elements List of comment Elements.
+	 * @param int   $max_depth The maximum hierarchical depth.
+	 * @param int   $page_num The specific page number, beginning with 1.
+	 * @param int   $per_page Per page counter.
+	 *
+	 * @return string XHTML of the specified page of elements.
+	 */
+	public function paged_walk( $elements, $max_depth, $page_num, $per_page ) {
+		if ( empty( $elements ) || $max_depth < - 1 ) {
+			return '';
+		}
+
+		$args = array_slice( func_get_args(), 4 );
+
+		$url = get_rest_url( get_current_blog_id(), 'amp/v1/comments/' . get_the_ID() );
+		if ( strpos( $url, 'http:' ) === 0 ) {
+			$url = substr( $url, 5 );
+		}
+		// @todo Identify arguments and make filterable/settable.
+		$output  = '<amp-list src="' . esc_attr( $url ) . '" height="200" width="auto" single-item="true" layout="flex-item">';
+		$output .= '<template type="amp-mustache"></template>';
+		$output .= '<div overflow role="button" aria-label="' . esc_attr__( 'Show more', 'amp' ) . '" class="list-overflow ampstart-btn caps">' . esc_html__( 'Show more', 'amp' ) . '</div>';
+		$output .= '<div fallback class="amp-fallback amp-comments-notice amp-error"><p>' . esc_html__( 'Could not load comments.', 'amp' ) . '</p></div>';
+		$output .= '</amp-list>';
+		$output .= '<comment-template>';
+		$output .= parent::paged_walk( $elements, $max_depth, $page_num, $per_page, $args[0] );
+		$output .= '</comment-template>';
+
+		return $output;
+	}
+}
diff --git a/includes/class-amp-theme-support.php b/includes/class-amp-theme-support.php
index c85bdd9f941..51704aabb29 100644
--- a/includes/class-amp-theme-support.php
+++ b/includes/class-amp-theme-support.php
@@ -26,6 +26,13 @@ class AMP_Theme_Support {
 	 */
 	const CUSTOM_STYLES_PLACEHOLDER = '/* AMP:CUSTOM_STYLES_PLACEHOLDER */';
 
+	/**
+	 * Replaced with the comments template.
+	 *
+	 * @var string
+	 */
+	const COMMENTS_TEMPLATE_PLACEHOLDER = '/* AMP:COMMENTS_TEMPLATE_PLACEHOLDER */';
+
 	/**
 	 * AMP Scripts.
 	 *
@@ -193,6 +200,17 @@ public static function register_hooks() {
 		 */
 		add_action( 'template_redirect', array( __CLASS__, 'start_output_buffering' ), 0 );
 
+		// Add Comments hooks.
+		add_filter( 'wp_list_comments_args', array( __CLASS__, 'add_amp_comments_template' ), PHP_INT_MAX );
+		add_filter( 'comments_array', array( __CLASS__, 'get_comments_template' ) );
+		add_action( 'comment_form_top', array( __CLASS__, 'add_amp_comment_form_templates' ), PHP_INT_MAX );
+		add_action( 'comment_form', array( __CLASS__, 'add_amp_comment_form_templates' ), PHP_INT_MAX );
+		// Filter dynamic data with mustache variable strings.
+		// @todo add additional filters for dynamic data like "get_comment_author_link", "get_comment_author_IP" etc...
+		add_filter( 'get_comment_date', array( __CLASS__, 'get_comment_date_template_string' ), PHP_INT_MAX );
+		add_filter( 'get_comment_time', array( __CLASS__, 'get_comment_time_template_string' ), PHP_INT_MAX );
+		add_filter( 'get_avatar_data', array( __CLASS__, 'get_avatar_data' ), PHP_INT_MAX );
+		add_filter( 'get_comment_ID', array( __CLASS__, 'get_comment_id_template_string' ), PHP_INT_MAX );
 		// @todo Add character conversion.
 	}
 
@@ -343,6 +361,126 @@ public static function add_amp_component_scripts() {
 		echo self::COMPONENT_SCRIPTS_PLACEHOLDER; // phpcs:ignore WordPress.Security.EscapeOutput, WordPress.XSS.EscapeOutput
 	}
 
+	/**
+	 * Add the comments template placeholder marker
+	 *
+	 * @param array $args the args for the comments list..
+	 * @return array Args to return.
+	 */
+	public static function add_amp_comments_template( $args ) {
+		$amp_walker     = new AMP_Comment_Walker();
+		$args['walker'] = $amp_walker;
+
+		return $args;
+	}
+
+	/**
+	 * Create a comments_flat array for generating the comment mustache template.
+	 *
+	 * @return array Flat array of comment placeholders.
+	 */
+	public static function get_comments_template() {
+
+		$_comment = array(
+			'comment_ID'           => '{{comment_ID}}',
+			'comment_post_ID'      => get_the_ID(),
+			'comment_author'       => '{{comment_author}}',
+			'comment_author_email' => '{{comment_author_email}}',
+			'comment_author_url'   => '{{comment_author_url}}',
+			'comment_author_IP'    => '{{comment_author_IP}}',
+			'comment_date'         => '{{comment_date}}',
+			'comment_date_gmt'     => '{{comment_date_gmt}}',
+			'comment_content'      => '{{comment_content}}',
+			'comment_karma'        => '{{comment_karma}}',
+			'comment_approved'     => '{{comment_approved}}',
+			'comment_agent'        => '{{comment_agent}}',
+			'comment_type'         => '{{comment_type}}',
+			'comment_parent'       => '',
+			'user_id'              => '{{user_id}}',
+		);
+
+		$comments = array();
+		$depth    = 5;
+		for ( $i = 0; $i < $depth; $i ++ ) {
+			$comment = new stdClass();
+			foreach ( $_comment as $key => $value ) {
+				if ( 'comment_ID' === $key ) {
+					$value = $i + 1;
+				}
+				if ( 'comment_parent' === $key && $i > 0 ) {
+					$value = $i;
+				}
+				$comment->{$key} = $value;
+			}
+			$comments[] = $comment;
+		}
+
+		return $comments;
+
+	}
+
+	/**
+	 * Adds the form submit success and fail templates.
+	 *
+	 * @param string $post_id The post ID if action is 'comment_form'.
+	 */
+	public static function add_amp_comment_form_templates( $post_id ) {
+		$output = '';
+		if ( empty( $post_id ) ) {
+			$output .= '<div id="amp-comment-form-fields">';
+		} else {
+			$output .= '</div>';
+			$output .= '<div submit-success><template type="amp-mustache">';
+			$output .= esc_html__( 'Your comment has been posted.', 'amp' );
+			$output .= sprintf( '<a class="amp-view-new-comment" href="{{comment_link}}">%s</a>', esc_html__( 'View Comment', 'amp' ) );
+			$output .= '</div></template>';
+			$output .= '<div submit-error><template type="amp-mustache">';
+			$output .= '<p class="amp-comment-submit-error">{{{error}}}</p>';
+			$output .= '</div></template>';
+		}
+
+		echo $output; // WPCS: XSS OK.
+	}
+
+	/**
+	 * Get avatar URL template string.
+	 *
+	 * @param array $args Avatar data args.
+	 * @return array Avatar data with url added.
+	 */
+	public static function get_avatar_data( $args ) {
+		$args['url'] = '{{comment_avatar_url}}';
+
+		return $args;
+	}
+
+	/**
+	 * Get comment ID string for template.
+	 *
+	 * @return string Mustache template string.
+	 */
+	public static function get_comment_id_template_string() {
+		return '{{comment_ID}}';
+	}
+
+	/**
+	 * Get comment date string for template.
+	 *
+	 * @return string Mustache template string.
+	 */
+	public static function get_comment_date_template_string() {
+		return '{{comment_date}}';
+	}
+
+	/**
+	 * Get somment time string for template.
+	 *
+	 * @return string Mustache template string.
+	 */
+	public static function get_comment_time_template_string() {
+		return '{{comment_time}}';
+	}
+
 	/**
 	 * Get canonical URL for current request.
 	 *
@@ -463,6 +601,23 @@ public static function get_amp_custom_styles() {
 		return $css;
 	}
 
+	/**
+	 * Determine the type of component script.
+	 *
+	 * @param string $component The component name.
+	 * @return string the type of component.
+	 */
+	public static function get_component_type( $component ) {
+		$component_types = apply_filters( 'amp_component_types', array(
+			'amp-mustache' => 'template',
+		) );
+
+		if ( ! empty( $component_types[ $component ] ) ) {
+			return $component_types[ $component ];
+		}
+		return 'element';
+	}
+
 	/**
 	 * Determine required AMP scripts.
 	 *
@@ -493,7 +648,8 @@ public static function get_amp_component_scripts() {
 		$scripts = '';
 		foreach ( $amp_scripts as $amp_script_component => $amp_script_source ) {
 			$scripts .= sprintf(
-				'<script async custom-element="%s" src="%s"></script>', // phpcs:ignore WordPress.WP.EnqueuedResources, WordPress.XSS.EscapeOutput.OutputNotEscaped
+				'<script async custom-%s="%s" src="%s"></script>', // phpcs:ignore WordPress.WP.EnqueuedResources, WordPress.XSS.EscapeOutput.OutputNotEscaped
+				self::get_component_type( $amp_script_component ),
 				$amp_script_component,
 				$amp_script_source
 			);
diff --git a/includes/sanitizers/class-amp-comments-sanitizer.php b/includes/sanitizers/class-amp-comments-sanitizer.php
new file mode 100644
index 00000000000..8cbfd5a9f5f
--- /dev/null
+++ b/includes/sanitizers/class-amp-comments-sanitizer.php
@@ -0,0 +1,100 @@
+<?php
+/**
+ * Class AMP_Comments_Sanitizer.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Comments_Sanitizer
+ *
+ * Strips and corrects attributes in forms.
+ */
+class AMP_Comments_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <form> tag to identify and process.
+	 *
+	 * @since 0.2
+	 */
+	public static $tag = 'comment-template';
+
+	/**
+	 * Sanitize the <img> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.2
+	 */
+	public function sanitize() {
+
+		/**
+		 * Node list.
+		 *
+		 * @var DOMNodeList $node
+		 */
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = 0; $i < $nodes->length; $i++ ) {
+			$node = $nodes->item( $i );
+			if ( ! $node instanceof DOMElement ) {
+				continue;
+			}
+
+			// Get the comment template layer parts. (wrapper, amp-list, template, comments-template).
+			$ol           = $node->parentNode;
+			$new_wrap     = $node->parentNode->cloneNode();
+			$amp_list     = $ol->getElementsByTagName( 'amp-list' )->item( 0 );
+			$amp_template = $ol->getElementsByTagName( 'template' )->item( 0 );
+			if ( ! $amp_list instanceof DOMElement || ! $amp_template instanceof DOMElement ) {
+				continue;
+			}
+
+			// Move Dom parts to an AMP structure.
+			$new_wrap->appendChild( $node );
+			$amp_template->appendChild( $new_wrap );
+			$ol->parentNode->replaceChild( $amp_list, $ol );
+
+			// Convert Links for templating.
+			$links = $amp_template->getElementsByTagName( 'a' );
+			$this->convert_urls( $links, 'href' );
+
+			// Convert image src for templating.
+			$imgs = $amp_template->getElementsByTagName( 'amp-img' );
+			if ( $imgs->length ) {
+				$this->convert_urls( $imgs, 'src' );
+				$this->convert_urls( $imgs, 'srcset' );
+			}
+		}
+
+		// cleanup comments form.
+		$comment_form = $this->dom->getElementById( 'commentform' );
+		if ( $comment_form instanceof DOMElement ) {
+			$comment_form->setAttribute( 'on', 'submit-success:amp-comment-form-fields.hide' );
+		}
+	}
+
+	/**
+	 * Convert comment_[field]_url to mustache template strings.
+	 *
+	 * @since 0.2
+	 * @param DOMNodeList $node_list The list of nodes to convert.
+	 * @param string      $type The type of attribute to convert.
+	 */
+	private function convert_urls( $node_list, $type = 'href' ) {
+
+		for ( $a = 0; $a < $node_list->length; $a++ ) {
+			$node = $node_list->item( $a );
+			if ( ! $node->hasAttribute( $type ) ) {
+				continue;
+			}
+			$url = preg_replace( '/http[s]?:\/\/(comment_[a-z_]+_url)/', '{{$1}}', $node->getAttribute( $type ) );
+			$node->setAttribute( $type, $url );
+		}
+	}
+}
diff --git a/includes/sanitizers/class-amp-form-sanitizer.php b/includes/sanitizers/class-amp-form-sanitizer.php
new file mode 100644
index 00000000000..a8aa147cb95
--- /dev/null
+++ b/includes/sanitizers/class-amp-form-sanitizer.php
@@ -0,0 +1,81 @@
+<?php
+/**
+ * Class AMP_Form_Sanitizer.
+ *
+ * @package AMP
+ * @since 0.7
+ */
+
+/**
+ * Class AMP_Form_Sanitizer
+ *
+ * Strips and corrects attributes in forms.
+ *
+ * @since 0.7
+ */
+class AMP_Form_Sanitizer extends AMP_Base_Sanitizer {
+
+	/**
+	 * Tag.
+	 *
+	 * @var string HTML <form> tag to identify and process.
+	 *
+	 * @since 0.7
+	 */
+	public static $tag = 'form';
+
+	/**
+	 * Sanitize the <form> elements from the HTML contained in this instance's DOMDocument.
+	 *
+	 * @since 0.7
+	 */
+	public function sanitize() {
+
+		/**
+		 * Node list.
+		 *
+		 * @var DOMNodeList $node
+		 */
+		$nodes     = $this->dom->getElementsByTagName( self::$tag );
+		$num_nodes = $nodes->length;
+
+		if ( 0 === $num_nodes ) {
+			return;
+		}
+
+		for ( $i = $num_nodes - 1; $i >= 0; $i -- ) {
+			$node = $nodes->item( $i );
+			if ( ! $node instanceof DOMElement ) {
+				continue;
+			}
+
+			$method = 'get';
+			if ( $node->hasAttribute( 'method' ) ) {
+				$method = strtolower( $node->getAttribute( 'method' ) );
+			}
+
+			// Get the action URL.
+			if ( ! $node->hasAttribute( 'action' ) ) {
+				$action_url = esc_url_raw( '//' . $_SERVER['HTTP_HOST'] . wp_unslash( $_SERVER['REQUEST_URI'] ) ); // WPCS: ignore. input var okay, sanitization ok.
+			} else {
+				$action_url = $node->getAttribute( 'action' );
+			}
+
+			if ( strpos( $action_url, 'http:' ) === 0 ) {
+				$action_url = substr( $action_url, 5 );
+			}
+
+			if ( 'post' === $method ) {
+				$node->setAttribute( 'action-xhr', $action_url );
+				$node->removeAttribute( 'action' );
+			} else {
+				$node->setAttribute( 'action', $action_url );
+			}
+
+			// Set a target if needed.
+			if ( ! $node->hasAttribute( 'target' ) ) {
+				$node->setAttribute( 'target', '_top' );
+			}
+		}
+	}
+}
diff --git a/includes/utils/class-amp-dom-utils.php b/includes/utils/class-amp-dom-utils.php
index cea51615da8..6d640d8e459 100644
--- a/includes/utils/class-amp-dom-utils.php
+++ b/includes/utils/class-amp-dom-utils.php
@@ -59,6 +59,22 @@ public static function get_dom( $document ) {
 		// @todo In the future consider an AMP_DOMDocument subclass that does this automatically. See <https://github.com/Automattic/amp-wp/pull/895/files#r163825513>.
 		$document = self::convert_amp_bind_attributes( $document );
 
+		/*
+		 * Prevent amp-mustache syntax from getting URL-encoded in attributes when saveHTML is done.
+		 * While this is applying to the entire document, it only really matters inside of <template>
+		 * elements, since URL-encoding of curly braces in href attributes would not normally matter.
+		 * But when this is done inside of a <template> then it breaks Mustache. Since Mustache
+		 * is logic-less and curly braces are not unsafe for HTML, we can do a global replacement.
+		 * The replacement is done on the entire HTML document instead of just inside of the <template>
+		 * elements since it is faster and wouldn't change the outcome.
+		 */
+		$placeholders = self::get_mustache_tag_placeholders();
+		$document     = str_replace(
+			array_keys( $placeholders ),
+			array_values( $placeholders ),
+			$document
+		);
+
 		/*
 		 * Wrap in dummy tags, since XML needs one parent node.
 		 * It also makes it easier to loop through nodes.
@@ -98,6 +114,38 @@ public static function get_amp_bind_placeholder_prefix() {
 		return $attribute_prefix;
 	}
 
+	/**
+	 * Get amp-mustache tag/placeholder mappings.
+	 *
+	 * @since 0.7
+	 * @see \wpdb::placeholder_escape()
+	 *
+	 * @return array Mapping of mustache tag token to its placeholder.
+	 */
+	private static function get_mustache_tag_placeholders() {
+		static $placeholders;
+		if ( ! isset( $placeholders ) ) {
+			$salt = wp_rand();
+
+			// Note: The order of these tokens is important, as it determines the order of the order of the replacements.
+			$tokens       = array(
+				'{{{',
+				'}}}',
+				'{{#',
+				'{{^',
+				'{{/',
+				'{{/',
+				'{{',
+				'}}',
+			);
+			$placeholders = array();
+			foreach ( $tokens as $token ) {
+				$placeholders[ $token ] = '_amp_mustache_' . md5( $salt . $token );
+			}
+		}
+		return $placeholders;
+	}
+
 	/**
 	 * Replace AMP binding attributes with something that libxml can parse (as HTML5 data-* attributes).
 	 *
@@ -285,6 +333,14 @@ public static function get_content_from_dom_node( $dom, $node ) {
 
 		$html = self::restore_amp_bind_attributes( $html );
 
+		// Restore amp-mustache placeholders which were replaced to prevent URL-encoded corruption by saveHTML.
+		$placeholders = self::get_mustache_tag_placeholders();
+		$html         = str_replace(
+			array_values( $placeholders ),
+			array_keys( $placeholders ),
+			$html
+		);
+
 		/*
 		 * Travis w/PHP 7.1 generates <br></br> and <hr></hr> vs. <br/> and <hr/>, respectively.
 		 * Travis w/PHP 7.x generates <source ...></source> vs. <source ... />.  Etc.
diff --git a/tests/test-amp-comment-sanitizer.php b/tests/test-amp-comment-sanitizer.php
new file mode 100644
index 00000000000..da615c1ff7f
--- /dev/null
+++ b/tests/test-amp-comment-sanitizer.php
@@ -0,0 +1,118 @@
+<?php
+/**
+ * Form Sanitizer tests
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Form_Sanitizer_Test
+ *
+ * @group amp-comments
+ * @group amp-comment
+ */
+class AMP_Comment_Sanitizer_Test extends WP_UnitTestCase {
+
+	/**
+	 * Data strings for testing converter.
+	 *
+	 * @return array
+	 */
+	public function get_data() {
+		return array(
+			'no_comments'                            => array(
+				'<p>Lorem Ipsum Demet Delorit.</p>',
+				'<p>Lorem Ipsum Demet Delorit.</p>',
+			),
+			'no_amp_list'                            => array(
+				'<div><p><comment-template></comment-template></p></div>',
+				'<div><p><comment-template></comment-template></p></div>',
+			),
+			'no_amp_list_template'                   => array(
+				'<div><p><template></template><comment-template></comment-template></p></div>',
+				'<div><p><template></template><comment-template></comment-template></p></div>',
+			),
+			'amp_list_no_template'                   => array(
+				'<div><p><amp-list></amp-list><comment-template></comment-template></p></div>',
+				'<div><p><amp-list></amp-list><comment-template></comment-template></p></div>',
+			),
+			'amp_list_template_moved_empty_template' => array(
+				'<div><p><amp-list><template></template></amp-list><comment-template>{{#comment}}<div>comment_template</div>{{/comment}}</comment-template></p></div>',
+				'<div><amp-list><template><p><comment-template>{{#comment}}<div>comment_template</div>{{/comment}}</comment-template></p></template></amp-list></div>',
+			),
+			'url_template_strings'                   => array(
+				'<div><p><amp-list><template></template></amp-list><comment-template><div><a href="https://comment_author_url"></a></div></comment-template></p></div>',
+				'<div><amp-list><template><p><comment-template><div><a href="{{comment_author_url}}"></a></div></comment-template></p></template></amp-list></div>',
+			),
+		);
+	}
+
+	/**
+	 * Test html conversion.
+	 *
+	 * @param string $source The source HTML.
+	 * @param string $expected The expected HTML after conversion.
+	 * @dataProvider get_data
+	 */
+	public function test_converter( $source, $expected ) {
+
+		$dom       = AMP_DOM_Utils::get_dom_from_content( $source );
+		$sanitizer = new AMP_Comments_Sanitizer( $dom );
+		$sanitizer->sanitize();
+		$content = AMP_DOM_Utils::get_content_from_dom( $dom );
+		$this->assertEquals( $expected, $content );
+	}
+
+	/**
+	 * Test amp-list template build.
+	 */
+	public function test_template_build() {
+
+		$this->navigate_to_post();
+		$template = get_echo( 'comments_template' );
+
+		$amp_list = preg_match( '/amp-list/', $template );
+		$this->assertEquals( 1, $amp_list );
+
+		$amp_template = preg_match( '/<template type="amp-mustache">/', $template );
+		$this->assertEquals( 1, $amp_template );
+
+		$comment_template = preg_match( '/comment-template/', $template );
+		$this->assertEquals( 1, $comment_template );
+
+	}
+
+	/**
+	 * Test the scripts are added.
+	 */
+	public function test_scripts() {
+		$this->navigate_to_post();
+		$template = '<div class="comments">' . get_echo( 'comments_template' ) . '</div>';
+		$expected = array(
+			'amp-mustache' => 'https://cdn.ampproject.org/v0/amp-mustache-latest.js',
+			'amp-list'     => 'https://cdn.ampproject.org/v0/amp-list-latest.js',
+		);
+
+		$dom = AMP_DOM_Utils::get_dom_from_content( $template );
+
+		$comment_sanitizer = new AMP_Comments_Sanitizer( $dom );
+		$comment_sanitizer->sanitize();
+
+		$sanitizer = new AMP_Tag_And_Attribute_Sanitizer( $dom );
+		$sanitizer->sanitize();
+
+		$scripts = $sanitizer->get_scripts();
+		$this->assertEquals( $expected, $scripts );
+
+	}
+
+	/**
+	 * Helper to navigate to a test post.
+	 */
+	public function navigate_to_post() {
+		$post_id = $this->factory()->post->create( array( 'post_title' => 'Test' ) );
+		add_theme_support( 'amp' );
+		AMP_Theme_Support::init();
+		$this->go_to( get_permalink( $post_id ) );
+	}
+}
diff --git a/tests/test-amp-form-sanitizer.php b/tests/test-amp-form-sanitizer.php
new file mode 100644
index 00000000000..72a828bba8b
--- /dev/null
+++ b/tests/test-amp-form-sanitizer.php
@@ -0,0 +1,69 @@
+<?php
+/**
+ * Tests for form sanitisation.
+ *
+ * @package AMP
+ */
+
+/**
+ * Class AMP_Form_Sanitizer_Test
+ *
+ * @group amp-comments
+ * @group amp-form
+ */
+class AMP_Form_Sanitizer_Test extends WP_UnitTestCase {
+
+	/**
+	 * Data strings for testing converter.
+	 *
+	 * @return array
+	 */
+	public function get_data() {
+		return array(
+			'no_form'                           => array(
+				'<p>Lorem Ipsum Demet Delorit.</p>',
+				'<p>Lorem Ipsum Demet Delorit.</p>',
+			),
+			'form_with_get_method_http_action'  => array(
+				'<form method="GET" action="http://example.org/example-page/"></form>',
+				'<form method="GET" action="//example.org/example-page/" target="_top"></form>',
+			),
+			'form_with_post_method_http_action' => array(
+				'<form method="POST" action="http://example.org/example-page/"></form>',
+				'<form method="POST" action-xhr="//example.org/example-page/" target="_top"></form>',
+			),
+
+		);
+	}
+
+	/**
+	 * Test html conversion.
+	 *
+	 * @param string $source The source HTML.
+	 * @param string $expected The expected HTML after conversion.
+	 * @dataProvider get_data
+	 */
+	public function test_converter( $source, $expected ) {
+		$dom       = AMP_DOM_Utils::get_dom_from_content( $source );
+		$sanitizer = new AMP_Form_Sanitizer( $dom );
+		$sanitizer->sanitize();
+		$content = AMP_DOM_Utils::get_content_from_dom( $dom );
+		$this->assertEquals( $expected, $content );
+	}
+
+	/**
+	 * Test scripts.
+	 */
+	public function test_scripts() {
+		$source   = '<form method="POST" action-xhr="//example.org/example-page/" target="_top"></form>';
+		$expected = array( 'amp-form' => 'https://cdn.ampproject.org/v0/amp-form-latest.js' );
+
+		$dom                 = AMP_DOM_Utils::get_dom_from_content( $source );
+		$whitelist_sanitizer = new AMP_Tag_And_Attribute_Sanitizer( $dom );
+		$whitelist_sanitizer->sanitize();
+
+		$scripts = $whitelist_sanitizer->get_scripts();
+
+		$this->assertEquals( $expected, $scripts );
+	}
+}
diff --git a/tests/test-tag-and-attribute-sanitizer.php b/tests/test-tag-and-attribute-sanitizer.php
index f8923d5d841..dd86c039e19 100644
--- a/tests/test-tag-and-attribute-sanitizer.php
+++ b/tests/test-tag-and-attribute-sanitizer.php
@@ -317,7 +317,7 @@ public function get_data() {
 			),
 
 			'attribute_value_valid'                                     => array(
-				'<template type="amp-mustache">Template Data</template>',
+				'<template type="amp-mustache">Hello {{world}}! <a href="{{user_url}}" title="{{user_name}}">Homepage</a> User content: {{{some_formatting}}} A guy with Mustache: :-{). {{#returning}}Welcome back!{{/returning}} {{^returning}}Welcome for the first time!{{/returning}} </template>',
 				null,
 				array( 'amp-mustache' ),
 			),