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 365c4f6..3e0071f 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
@@ -431,11 +431,11 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 		}
 
 		/*
-		 * Do not allow a comment to be created with an empty string for
+		 * Do not allow a comment to be created with missing or empty
 		 * comment_content. See wp_handle_comment_submission().
 		 */
-		if ( '' === $prepared_comment['comment_content'] ) {
-			return new WP_Error( 'rest_comment_content_invalid', __( 'Comment content is invalid.' ), array( 'status' => 400 ) );
+		if ( empty( $prepared_comment['comment_content'] ) ) {
+			return new WP_Error( 'rest_comment_content_required', __( 'Missing comment content.' ), array( 'status' => 400 ) );
 		}
 
 		// Setting remaining values before wp_insert_comment so we can use wp_allow_comment().
@@ -636,6 +636,10 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 				return $prepared_args;
 			}
 
+			if ( isset( $prepared_args['comment_content'] ) && empty( $prepared_args['comment_content'] ) ) {
+				return new WP_Error( 'rest_comment_invalid_content', __( 'Comment content cannot be empty.' ), array( 'status' => 400 ) );
+			}
+
 			$prepared_args['comment_ID'] = $id;
 
 			$check_comment_lengths = wp_check_comment_data_max_lengths( $prepared_args );
@@ -1064,11 +1068,6 @@ class WP_REST_Comments_Controller extends WP_REST_Controller {
 			}
 		}
 
-		// Require 'comment_content' unless only the 'comment_status' is being updated.
-		if ( ! empty( $prepared_comment ) && ! isset( $prepared_comment['comment_content'] ) ) {
-			return new WP_Error( 'rest_comment_content_required', __( 'Missing comment content.' ), array( 'status' => 400 ) );
-		}
-
 		/**
 		 * Filters a comment after it is prepared for the database.
 		 *
diff --git a/tests/phpunit/tests/rest-api/rest-comments-controller.php b/tests/phpunit/tests/rest-api/rest-comments-controller.php
index e225cbc..e5ab1b7 100644
--- a/tests/phpunit/tests/rest-api/rest-comments-controller.php
+++ b/tests/phpunit/tests/rest-api/rest-comments-controller.php
@@ -827,6 +827,30 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$this->assertEquals( self::$post_id, $data['post'] );
 	}
 
+	public function test_create_item_no_content() {
+		wp_set_current_user( 0 );
+
+		$params = array(
+			'post'         => self::$post_id,
+			'author_name'  => 'Comic Book Guy',
+			'author_email' => 'cbg@androidsdungeon.com',
+			'author_url'   => 'http://androidsdungeon.com',
+			'content'      => '',
+			'date'         => '2014-11-07T10:14:25',
+		);
+
+		$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_content_required', $response, 400 );
+
+		unset( $params['content'] );
+		$request->set_body( wp_json_encode( $params ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertErrorResponse( 'rest_comment_content_required', $response, 400 );
+	}
+
 	public function test_create_item_using_accepted_content_raw_value() {
 		wp_set_current_user( 0 );
 
@@ -929,7 +953,7 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$this->assertArrayHasKey( 'author_email', $data['data']['params'] );
 	}
 
-	public function test_create_item_invalid_blank_content() {
+	public function test_create_item_invalid_no_content() {
 		wp_set_current_user( 0 );
 
 		$params = array(
@@ -937,7 +961,6 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 			'author_name'  => 'Reverend Lovejoy',
 			'author_email' => 'lovejoy@example.com',
 			'author_url'   => 'http://timothylovejoy.jr',
-			'content'      => '',
 		);
 
 		$request = new WP_REST_Request( 'POST', '/wp/v2/comments' );
@@ -945,7 +968,12 @@ 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_content_invalid', $response, 400 );
+		$this->assertErrorResponse( 'rest_comment_content_required', $response, 400 );
+
+		$params['content'] = '';
+		$request->set_body( wp_json_encode( $params ) );
+		$response = $this->server->dispatch( $request );
+		$this->assertErrorResponse( 'rest_comment_content_required', $response, 400 );
 	}
 
 	public function test_create_item_invalid_date() {
@@ -1618,6 +1646,25 @@ class WP_Test_REST_Comments_Controller extends WP_Test_REST_Controller_Testcase
 		$this->assertEquals( '2014-11-07T10:14:25', $comment['date'] );
 	}
 
+	public function test_update_item_no_content() {
+		$post_id = $this->factory->post->create();
+
+		wp_set_current_user( self::$admin_id );
+
+		$request = new WP_REST_Request( 'PUT', sprintf( '/wp/v2/comments/%d', self::$approved_id ) );
+		$request->set_param( 'author_email', 'another@email.com' );
+
+		// Sending a request without content is fine.
+		$response = $this->server->dispatch( $request );
+		$this->assertEquals( 200, $response->get_status() );
+
+		// Sending a request with empty comment is not fine.
+		$request->set_param( 'author_email', 'yetanother@email.com' );
+		$request->set_param( 'content', '' );
+		$response = $this->server->dispatch( $request );
+		$this->assertErrorResponse( 'rest_comment_invalid_content', $response, 400 );
+	}
+
 	public function test_update_comment_status() {
 		wp_set_current_user( self::$admin_id );