diff --git a/src/wp-admin/includes/file.php b/src/wp-admin/includes/file.php
index 2a0c879b10..2f90b74dbd 100644
--- a/src/wp-admin/includes/file.php
+++ b/src/wp-admin/includes/file.php
@@ -993,9 +993,32 @@ function download_url( $url, $timeout = 300 ) {
 		return $response;
 	}
 
-	if ( 200 != wp_remote_retrieve_response_code( $response ) ) {
+	$response_code = wp_remote_retrieve_response_code( $response );
+
+	if ( 200 != $response_code ) {
+		$data = array(
+			'code' => $response_code,
+		);
+
+		// Retrieve a sample of the response body for debugging purposes.
+		$tmpf = fopen( $tmpfname, 'rb' );
+		if ( $tmpf ) {
+			/**
+			 * Filters the maximum error response body size in `download_url()`.
+			 *
+			 * @since 5.0.0
+			 *
+			 * @see download_url()
+			 *
+			 * @param int $size The maximum error response body size. Default 1 KB.
+			 */
+			$response_size = apply_filters( 'download_url_error_max_body_size', KB_IN_BYTES );
+			$data['body']  = fread( $tmpf, $response_size );
+			fclose( $tmpf );
+		}
+
 		unlink( $tmpfname );
-		return new WP_Error( 'http_404', trim( wp_remote_retrieve_response_message( $response ) ) );
+		return new WP_Error( 'http_404', trim( wp_remote_retrieve_response_message( $response ) ), $data );
 	}
 
 	$content_md5 = wp_remote_retrieve_header( $response, 'content-md5' );
diff --git a/tests/phpunit/tests/admin/includesFile.php b/tests/phpunit/tests/admin/includesFile.php
index 7ecbd0ef2b..a25e79974e 100644
--- a/tests/phpunit/tests/admin/includesFile.php
+++ b/tests/phpunit/tests/admin/includesFile.php
@@ -31,4 +31,44 @@ class Tests_Admin_includesFile extends WP_UnitTestCase {
 		update_option( 'siteurl', $siteurl );
 		$_SERVER['SCRIPT_FILENAME'] = $sfn;
 	}
+
+	/**
+	 * @ticket 43329
+	 */
+	public function test_download_url_non_200_response_code() {
+		add_filter( 'pre_http_request', array( $this, '_fake_download_url_non_200_response_code' ), 10, 3 );
+
+		$error = download_url( 'test_download_url_non_200' );
+		$this->assertWPError( $error );
+		$this->assertEquals( array(
+			'code' => 418,
+			'body' => 'This is an unexpected error message from your favorite server.',
+		), $error->get_error_data() );
+
+		add_filter( 'download_url_error_max_body_size', array( $this, '__return_5' ) );
+
+		$error = download_url( 'test_download_url_non_200' );
+		$this->assertWPError( $error );
+		$this->assertEquals( array(
+			'code' => 418,
+			'body' => 'This ',
+		), $error->get_error_data() );
+
+		remove_filter( 'download_url_error_max_body_size', array( $this, '__return_5' ) );
+		remove_filter( 'pre_http_request', array( $this, '_fake_download_url_non_200_response_code' ) );
+	}
+
+	public function _fake_download_url_non_200_response_code( $response, $args, $url ) {
+		file_put_contents( $args['filename'], 'This is an unexpected error message from your favorite server.' );
+		return array(
+			'response' => array(
+				'code'    => 418,
+				'message' => "I'm a teapot!",
+			),
+		);
+	}
+
+	public function __return_5() {
+		return 5;
+	}
 }