diff --git a/src/wp-includes/comment.php b/src/wp-includes/comment.php
index 0fb9f01093..f098910ea5 100644
--- a/src/wp-includes/comment.php
+++ b/src/wp-includes/comment.php
@@ -3065,7 +3065,7 @@ function wp_handle_comment_submission( $comment_data ) {
 	$comment_type = '';
 
 	if ( get_option( 'require_name_email' ) && ! $user->exists() ) {
-		if ( 6 > strlen( $comment_author_email ) || '' == $comment_author ) {
+		if ( '' == $comment_author_email || '' == $comment_author ) {
 			return new WP_Error( 'require_name_email', __( '<strong>ERROR</strong>: please fill the required fields (name, email).' ), 200 );
 		} elseif ( ! is_email( $comment_author_email ) ) {
 			return new WP_Error( 'require_valid_email', __( '<strong>ERROR</strong>: please enter a valid email address.' ), 200 );
diff --git a/src/wp-includes/formatting.php b/src/wp-includes/formatting.php
index a057cce063..6b96097e83 100644
--- a/src/wp-includes/formatting.php
+++ b/src/wp-includes/formatting.php
@@ -2872,7 +2872,7 @@ function is_email( $email, $deprecated = false ) {
 		_deprecated_argument( __FUNCTION__, '3.0.0' );
 
 	// Test for the minimum length the email can be
-	if ( strlen( $email ) < 3 ) {
+	if ( strlen( $email ) < 6 ) {
 		/**
 		 * Filters whether an email address is valid.
 		 *
@@ -3109,7 +3109,7 @@ function iso8601_to_datetime( $date_string, $timezone = 'user' ) {
  */
 function sanitize_email( $email ) {
 	// Test for the minimum length the email can be
-	if ( strlen( $email ) < 3 ) {
+	if ( strlen( $email ) < 6 ) {
 		/**
 		 * Filters a sanitized email address.
 		 *
diff --git a/src/wp-includes/rest-api.php b/src/wp-includes/rest-api.php
index ec7c50d27b..57e4e9f6fd 100644
--- a/src/wp-includes/rest-api.php
+++ b/src/wp-includes/rest-api.php
@@ -1077,11 +1077,7 @@ function rest_validate_value_from_schema( $value, $args, $param = '' ) {
 				break;
 
 			case 'email' :
-				// is_email() checks for 3 characters (a@b), but
-				// wp_handle_comment_submission() requires 6 characters (a@b.co)
-				//
-				// https://core.trac.wordpress.org/ticket/38506
-				if ( ! is_email( $value ) || strlen( $value ) < 6 ) {
+				if ( ! is_email( $value ) ) {
 					return new WP_Error( 'rest_invalid_email', __( 'Invalid email address.' ) );
 				}
 				break;
diff --git a/tests/phpunit/tests/formatting/IsEmail.php b/tests/phpunit/tests/formatting/IsEmail.php
index 0432fa62da..feff3ed916 100644
--- a/tests/phpunit/tests/formatting/IsEmail.php
+++ b/tests/phpunit/tests/formatting/IsEmail.php
@@ -9,7 +9,8 @@ class Tests_Formatting_IsEmail extends WP_UnitTestCase {
 			"bob@example.com",
 			"phil@example.info",
 			"ace@204.32.222.14",
-			"kevin@many.subdomains.make.a.happy.man.edu"
+			"kevin@many.subdomains.make.a.happy.man.edu",
+			"a@b.co",
 			);
 		foreach ( $data as $datum ) {
 			$this->assertEquals( $datum, is_email( $datum ), $datum );
@@ -22,7 +23,8 @@ class Tests_Formatting_IsEmail extends WP_UnitTestCase {
 			'http://bob.example.com/',
 			"sif i'd give u it, spamer!1",
 			"com.exampleNOSPAMbob",
-			"bob@your mom"
+			"bob@your mom",
+			"a@b.c",
 			);
 		foreach ($data as $datum) {
 			$this->assertFalse(is_email($datum), $datum);