diff --git a/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php b/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
index b07ced4458..9fe4f90e52 100644
--- a/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
+++ b/src/wp-includes/rest-api/endpoints/class-wp-rest-comments-controller.php
@@ -508,17 +508,9 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 
 		// Honor the discussion setting that requires a name and email address of the comment author.
 		if ( get_option( 'require_name_email' ) ) {
-			if ( ! isset( $prepared_comment['comment_author'] ) && ! isset( $prepared_comment['comment_author_email'] ) ) {
+			if ( empty( $prepared_comment['comment_author'] ) || empty( $prepared_comment['comment_author_email'] ) ) {
 				return new WP_Error( 'rest_comment_author_data_required', __( 'Creating a comment requires valid author name and email values.' ), array( 'status' => 400 ) );
 			}
-
-			if ( ! isset( $prepared_comment['comment_author'] ) ) {
-				return new WP_Error( 'rest_comment_author_required', __( 'Creating a comment requires a valid author name.' ), array( 'status' => 400 ) );
-			}
-
-			if ( ! isset( $prepared_comment['comment_author_email'] ) ) {
-				return new WP_Error( 'rest_comment_author_email_required', __( 'Creating a comment requires a valid author email.' ), array( 'status' => 400 ) );
-			}
 		}
 
 		if ( ! isset( $prepared_comment['comment_author_email'] ) ) {
@@ -1155,6 +1147,10 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 					'type'         => 'string',
 					'format'       => 'email',
 					'context'      => array( 'edit' ),
+					'arg_options'  => array(
+						'sanitize_callback' => array( $this, 'check_comment_author_email' ),
+						'validate_callback' => null, // skip built-in validation of 'email'.
+					),
 				),
 				'author_ip'     => array(
 					'description'  => __( 'IP address for the object author.' ),
@@ -1581,4 +1577,33 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 
 		return current_user_can( 'edit_comment', $comment->comment_ID );
 	}
+
+	/**
+	 * Checks a comment author email for validity.
+	 *
+	 * Accepts either a valid email address or empty string as a valid comment
+	 * author email address. Setting the comment author email to an empty
+	 * string is allowed when a comment is being updated.
+	 *
+	 * @since 4.7.0
+	 *
+	 * @param string          $value   Author email value submitted.
+	 * @param WP_REST_Request $request Full details about the request.
+	 * @param string          $param   The parameter name.
+	 * @return WP_Error|string The sanitized email address, if valid,
+	 *                         otherwise an error.
+	 */
+	public function check_comment_author_email( $value, $request, $param ) {
+		$email = (string) $value;
+		if ( empty( $email ) ) {
+			return $email;
+		}
+
+		$check_email = rest_validate_request_arg( $email, $request, $param );
+		if ( is_wp_error( $check_email ) ) {
+			return $check_email;
+		}
+
+		return $email;
+	}
 }
diff --git a/tests/phpunit/tests/rest-api/rest-comments-controller.php b/tests/phpunit/tests/rest-api/rest-comments-controller.php
index 1daa35ea38..a103d21c5c 100644
--- a/tests/phpunit/tests/rest-api/rest-comments-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-comments-controller.php
@@ -97,10 +97,6 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		}
 	}
 
-	public function tearDown() {
-		parent::tearDown();
-	}
-
 	public function test_register_routes() {
 		$routes = $this->server->get_routes();
 
@@ -987,30 +983,10 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$this->assertEquals( $params['content']['raw'], $new_comment->comment_content );
 	}
 
-	public function test_create_comment_missing_required_author_name_and_email_per_option_value() {
+	public function test_create_comment_missing_required_author_name() {
 		add_filter( 'rest_allow_anonymous_comments', '__return_true' );
 		update_option( 'require_name_email', 1 );
 
-		$params = array(
-			'post'    => self::$post_id,
-			'content' => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
-		);
-
-		$request = new WP_REST_Request( 'POST', '/wp/v2/comments' );
-		$request->add_header( 'content-type', 'application/json' );
-		$request->set_body( wp_json_encode( $params ) );
-
-		$response = $this->server->dispatch( $request );
-
-		$this->assertErrorResponse( 'rest_comment_author_data_required', $response, 400 );
-
-		update_option( 'require_name_email', 0 );
-	}
-
-	public function test_create_comment_missing_required_author_name_per_option_value() {
-		wp_set_current_user( self::$admin_id );
-		update_option( 'require_name_email', 1 );
-
 		$params = array(
 			'post'         => self::$post_id,
 			'author_email' => 'ekrabappel@springfield-elementary.edu',
@@ -1022,12 +998,31 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$request->set_body( wp_json_encode( $params ) );
 
 		$response = $this->server->dispatch( $request );
-		$this->assertErrorResponse( 'rest_comment_author_required', $response, 400 );
 
-		update_option( 'require_name_email', 0 );
+		$this->assertErrorResponse( 'rest_comment_author_data_required', $response, 400 );
 	}
 
-	public function test_create_comment_missing_required_author_email_per_option_value() {
+	public function test_create_comment_empty_required_author_name() {
+		add_filter( 'rest_allow_anonymous_comments', '__return_true' );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'author_name'  => '',
+			'author_email' => 'ekrabappel@springfield-elementary.edu',
+			'post'         => self::$post_id,
+			'content'      => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'POST', '/wp/v2/comments' );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+
+		$this->assertErrorResponse( 'rest_comment_author_data_required', $response, 400 );
+	}
+
+	public function test_create_comment_missing_required_author_email() {
 		wp_set_current_user( self::$admin_id );
 		update_option( 'require_name_email', 1 );
 
@@ -1042,9 +1037,26 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$request->set_body( wp_json_encode( $params ) );
 
 		$response = $this->server->dispatch( $request );
-		$this->assertErrorResponse( 'rest_comment_author_email_required', $response, 400 );
+		$this->assertErrorResponse( 'rest_comment_author_data_required', $response, 400 );
+	}
 
-		update_option( 'require_name_email', 0 );
+	public function test_create_comment_empty_required_author_email() {
+		wp_set_current_user( self::$admin_id );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'post'         => self::$post_id,
+			'author_name'  => 'Edna Krabappel',
+			'author_email' => '',
+			'content'      => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'POST', '/wp/v2/comments' );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertErrorResponse( 'rest_comment_author_data_required', $response, 400 );
 	}
 
 	public function test_create_comment_author_email_too_short() {
@@ -1992,6 +2004,100 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$this->assertEquals( $params['date_gmt'], mysql_to_rfc3339( $updated->comment_date_gmt ) );
 	}
 
+	public function test_update_comment_author_email_only() {
+		wp_set_current_user( self::$editor_id );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'post'         => self::$post_id,
+			'author_email' => 'ekrabappel@springfield-elementary.edu',
+			'content'      => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
+	public function test_update_comment_empty_author_name() {
+		wp_set_current_user( self::$editor_id );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'author_name'  => '',
+			'author_email' => 'ekrabappel@springfield-elementary.edu',
+			'post'         => self::$post_id,
+			'content'      => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
+	public function test_update_comment_author_name_only() {
+		wp_set_current_user( self::$admin_id );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'post'        => self::$post_id,
+			'author_name' => 'Edna Krabappel',
+			'content'     => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
+	public function test_update_comment_empty_author_email() {
+		wp_set_current_user( self::$admin_id );
+		update_option( 'require_name_email', 1 );
+
+		$params = array(
+			'post'         => self::$post_id,
+			'author_name'  => 'Edna Krabappel',
+			'author_email' => '',
+			'content'      => 'Now, I don\'t want you to worry class. These tests will have no affect on your grades. They merely determine your future social status and financial success. If any.',
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+	}
+
+	public function test_update_comment_author_email_too_short() {
+		wp_set_current_user( self::$admin_id );
+
+		$params = array(
+			'post'         => self::$post_id,
+			'author_name'  => 'Homer J. Simpson',
+			'author_email' => 'a@b',
+			'content'      => 'in this house, we obey the laws of thermodynamics!',
+		);
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_body( wp_json_encode( $params ) );
+		$response = $this->server->dispatch( $request );
+
+		$this->assertErrorResponse( 'rest_invalid_param', $response, 400 );
+		$data = $response->get_data();
+		$this->assertArrayHasKey( 'author_email', $data['data']['params'] );
+	}
+
 	public function test_update_comment_invalid_type() {
 		wp_set_current_user( self::$admin_id );