diff --git src/wp-includes/pluggable.php src/wp-includes/pluggable.php
index aa632921c6..60c8cfca0b 100644
--- src/wp-includes/pluggable.php
+++ src/wp-includes/pluggable.php
@@ -1606,6 +1606,10 @@ if ( ! function_exists( 'wp_notify_postauthor' ) ) :
 				$notify_message .= sprintf( __( 'Email: %s' ), $comment->comment_author_email ) . "\r\n";
 				/* translators: %s: Trackback/pingback/comment author URL. */
 				$notify_message .= sprintf( __( 'URL: %s' ), $comment->comment_author_url ) . "\r\n";
+				if ( 0 !== (int) $comment->comment_parent ) {
+					/* translators: Comment parent. 1: Comment parent URL */
+					$notify_message .= sprintf( __( 'In reply to: %s' ), admin_url( "comment.php?action=editcomment&c={$comment->comment_parent}" ) ) . "\r\n";
+				}
 				/* translators: %s: Comment text. */
 				$notify_message .= sprintf( __( 'Comment: %s' ), "\r\n" . $comment_content ) . "\r\n\r\n";
 				$notify_message .= __( 'You can see all comments on this post here:' ) . "\r\n";
@@ -1781,6 +1785,10 @@ if ( ! function_exists( 'wp_notify_moderator' ) ) :
 				$notify_message .= sprintf( __( 'Email: %s' ), $comment->comment_author_email ) . "\r\n";
 				/* translators: %s: Trackback/pingback/comment author URL. */
 				$notify_message .= sprintf( __( 'URL: %s' ), $comment->comment_author_url ) . "\r\n";
+				if ( 0 !== (int) $comment->comment_parent ) {
+					/* translators: Comment parent. 1: Comment parent URL */
+					$notify_message .= sprintf( __( 'In reply to: %s' ), admin_url( "comment.php?action=editcomment&c={$comment->comment_parent}" ) ) . "\r\n";
+				}
 				/* translators: %s: Comment text. */
 				$notify_message .= sprintf( __( 'Comment: %s' ), "\r\n" . $comment_content ) . "\r\n\r\n";
 				break;
diff --git tests/phpunit/tests/comment.php tests/phpunit/tests/comment.php
index 720a805062..6bf33b04db 100644
--- tests/phpunit/tests/comment.php
+++ tests/phpunit/tests/comment.php
@@ -6,6 +6,7 @@
 class Tests_Comment extends WP_UnitTestCase {
 	protected static $user_id;
 	protected static $post_id;
+	protected static $notify_message;
 
 	public function setUp() {
 		parent::setUp();
@@ -434,6 +435,117 @@ class Tests_Comment extends WP_UnitTestCase {
 		$this->assertFalse( $sent );
 	}
 
+	/**
+	 * @ticket 43805
+	 */
+	public function test_wp_new_comment_notify_postauthor_content_should_include_link_to_parent() {
+		self::$notify_message = '';
+
+		$c = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+			)
+		);
+
+		$r = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_parent'   => $c,
+			)
+		);
+
+		add_filter( 'comment_notification_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+		$sent = wp_new_comment_notify_postauthor( $r );
+		remove_filter( 'comment_notification_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+
+		$pattern = addcslashes( admin_url( "comment.php?action=editcomment&c={$c}" ), '/?&' );
+
+		$this->assertEquals( 1, preg_match( '/' . $pattern . '/', self::$notify_message ) );
+	}
+
+	/**
+	 * @ticket 43805
+	 */
+	public function test_wp_new_comment_notify_postauthor_content_shouldnot_include_link_to_parent() {
+		self::$notify_message = '';
+
+		$c = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+			)
+		);
+
+		add_filter( 'comment_notification_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+		$sent = wp_new_comment_notify_postauthor( $c );
+		remove_filter( 'comment_notification_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+
+		$pattern = addcslashes( admin_url( "comment.php?action=editcomment&c={$c}" ), '/?&' );
+
+		$this->assertNotEquals( 1, preg_match( '/' . $pattern . '/', self::$notify_message ) );
+	}
+
+	/**
+	 * @ticket 43805
+	 */
+	public function test_wp_new_comment_notify_moderator_content_should_include_link_to_parent() {
+		self::$notify_message = '';
+
+		$c = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+			)
+		);
+
+		$r = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_parent'   => $c,
+				'comment_approved' => '0',
+			)
+		);
+
+		add_filter( 'comment_moderation_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+		$sent = wp_new_comment_notify_moderator( $r );
+		remove_filter( 'comment_moderation_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+
+		$pattern = addcslashes( admin_url( "comment.php?action=editcomment&c={$c}" ), '/?&' );
+
+		$this->assertEquals( 1, preg_match( '/' . $pattern . '/', self::$notify_message ) );
+	}
+
+	/**
+	 * @ticket 43805
+	 */
+	public function test_wp_new_comment_notify_moderator_content_shouldnot_include_link_to_parent() {
+		self::$notify_message = '';
+
+		$c = self::factory()->comment->create(
+			array(
+				'comment_post_ID'  => self::$post_id,
+				'comment_approved' => '0'
+			)
+		);
+
+		add_filter( 'comment_moderation_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+		$sent = wp_new_comment_notify_moderator( $c );
+		remove_filter( 'comment_moderation_text', array( $this, 'comment_notification_text_get' ), 10, 1 );
+
+		$pattern = addcslashes( admin_url( "comment.php?action=editcomment&c={$c}" ), '/?&' );
+
+		$this->assertNotEquals( 1, preg_match( '/' . $pattern . '/', self::$notify_message ) );
+	}
+
+	/**
+	 * Callback for the `comment_notification_text` & `comment_moderation_text` filters.
+	 *
+	 * @param  string $notify_message The comment notification or moderation email text.
+	 * @return string
+	 */
+	public function comment_notification_text_get( $notify_message = '' ) {
+		self::$notify_message = $notify_message;
+		return $notify_message;
+	}
+
 	/**
 	 * @ticket 12431
 	 */