diff --git a/lib/outputlib.php b/lib/outputlib.php
index f44c12e9c18..119a8f0b503 100644
--- a/lib/outputlib.php
+++ b/lib/outputlib.php
@@ -925,6 +925,11 @@ class theme_config {
     public function editor_css_url($encoded=true) {
         global $CFG;
         $rev = theme_get_revision();
+        $type = 'editor';
+        if (right_to_left()) {
+            $type .= '-rtl';
+        }
+
         if ($rev > -1) {
             $themesubrevision = theme_get_sub_revision_for_theme($this->name);
 
@@ -936,13 +941,19 @@ class theme_config {
 
             $url = new moodle_url("/theme/styles.php");
             if (!empty($CFG->slasharguments)) {
-                $url->set_slashargument('/'.$this->name.'/'.$rev.'/editor', 'noparam', true);
+                $url->set_slashargument("{$this->name}/{$rev}/{$type}", 'noparam', true);
             } else {
-                $url->params(array('theme'=>$this->name,'rev'=>$rev, 'type'=>'editor'));
+                $url->params([
+                    'theme' => $this->name,
+                    'rev' => $rev,
+                    'type' => $type,
+                ]);
             }
         } else {
-            $params = array('theme'=>$this->name, 'type'=>'editor');
-            $url = new moodle_url('/theme/styles_debug.php', $params);
+            $url = new moodle_url('/theme/styles_debug.php', [
+                'theme' => $this->name,
+                'type' => $type,
+            ]);
         }
         return $url;
     }
diff --git a/theme/styles.php b/theme/styles.php
index 2b25d142401..c64eb6546bc 100644
--- a/theme/styles.php
+++ b/theme/styles.php
@@ -67,7 +67,7 @@ if (!is_null($themesubrev)) {
 }
 
 // Check that type fits into the expected values.
-if (!in_array($type, ['all', 'all-rtl', 'editor'])) {
+if (!in_array($type, ['all', 'all-rtl', 'editor', 'editor-rtl'])) {
     css_send_css_not_found();
 }
 
@@ -103,7 +103,7 @@ require("$CFG->dirroot/lib/setup.php");
 
 $theme = theme_config::load($themename);
 $theme->force_svg_use($usesvg);
-$theme->set_rtl_mode($type === 'all-rtl' ? true : false);
+$theme->set_rtl_mode(substr($type, -4) === '-rtl');
 
 $themerev = theme_get_revision();
 $currentthemesubrev = theme_get_sub_revision_for_theme($themename);
@@ -125,7 +125,7 @@ if ($themerev <= 0 or $themerev != $rev or $themesubrev != $currentthemesubrev)
 
 make_localcache_directory('theme', false);
 
-if ($type === 'editor') {
+if ($type === 'editor' || $type === 'editor-rtl') {
     $csscontent = $theme->get_css_content_editor();
 
     if ($cache) {