diff --git a/system/src/Grav/Common/Utils.php b/system/src/Grav/Common/Utils.php
index 683f17dab..85631966a 100644
--- a/system/src/Grav/Common/Utils.php
+++ b/system/src/Grav/Common/Utils.php
@@ -270,6 +270,25 @@ abstract class Utils
             } else {
                 $new_length = $size;
                 header("Content-Length: " . $size);
+
+                if (Grav::instance()['config']->get('system.cache.enabled')) {
+                    $expires = Grav::instance()['config']->get('system.pages.expires');
+                    if ($expires > 0) {
+                        $expires_date = gmdate('D, d M Y H:i:s T', time() + $expires);
+                        header('Cache-Control: max-age=' . $expires);
+                        header('Expires: ' . $expires_date);
+                        header('Pragma: cache');
+                    }
+                    header('Last-Modified: ' . gmdate("D, d M Y H:i:s T", filemtime($file)));
+
+                    // Return 304 Not Modified if the file is already cached in the browser
+                    if (isset($_SERVER['HTTP_IF_MODIFIED_SINCE']) && 
+                        strtotime($_SERVER['HTTP_IF_MODIFIED_SINCE']) >= filemtime($file))
+                    {
+                        header('HTTP/1.1 304 Not Modified');
+                        exit();
+                    }
+                }
             }
 
             /* output the file itself */