diff --git a/booking.email_manually.inc b/booking.email_manually.inc
index 994a35e..ad36890 100644
--- a/booking.email_manually.inc
+++ b/booking.email_manually.inc
@@ -131,6 +131,7 @@ function booking_manual_email_form($form, &$form_state)
 		'#title' => t('Email attachment'),
 		'#description' => t('Attach a file to be emailed. Note that this only works with custom email types. File must be 10MB or less, and extension must be one of: ' . variable_get('booking_email_allowed_attachments', 'pdf docx')),
     '#upload_location' => 'public://bookings/emails',
+    '#attributes' => array('multiple' => 'multiple'),
     '#upload_validators' => array(
       'file_validate_size' => array(10*1024*1024),
       'file_validate_extensions' => array(variable_get('booking_email_allowed_attachments', 'pdf docx')),