diff --git a/app/helpers/application_helper.rb b/app/helpers/application_helper.rb
index 8a70d56793c..13fa60bd86d 100644
--- a/app/helpers/application_helper.rb
+++ b/app/helpers/application_helper.rb
@@ -295,7 +295,7 @@ module ApplicationHelper
       [I18n.t("themes.light"), "light"],
       [I18n.t("themes.light_high_contrast"), "light_high_contrast"],
       [I18n.t("themes.dark"), "dark"],
-      [I18n.t("themes.sync_with_system"), "sync_with_system"]
+      [I18n.t("themes.sync_with_os"), "sync_with_os"]
     ]
   end
 
diff --git a/app/models/user_preference.rb b/app/models/user_preference.rb
index 15428ebda81..2cecc9bf0a8 100644
--- a/app/models/user_preference.rb
+++ b/app/models/user_preference.rb
@@ -131,7 +131,7 @@ class UserPreference < ApplicationRecord
   end
 
   def sync_with_system_theme?
-    theme == "sync_with_system"
+    theme == "sync_with_os"
   end
 
   def high_contrast_theme?
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 7d06496d247..2ddd9a8e727 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -742,7 +742,7 @@ en:
     dark: "Dark"
     light: "Light"
     light_high_contrast: "Light high contrast"
-    sync_with_system: "Auto (system default)"
+    sync_with_os: "Automatic (match OS colour mode)"
 
   types:
     index:
diff --git a/config/schemas/user_preferences.schema.json b/config/schemas/user_preferences.schema.json
index 10d23409b11..dd4315cec28 100644
--- a/config/schemas/user_preferences.schema.json
+++ b/config/schemas/user_preferences.schema.json
@@ -11,7 +11,7 @@
                 },
                 "theme": {
                   "type": "string",
-                  "enum": ["light", "light_high_contrast", "dark", "sync_with_system"]
+                  "enum": ["light", "light_high_contrast", "dark", "sync_with_os"]
                 },
                 "disable_keyboard_shortcuts": {
                     "type": "boolean"
diff --git a/frontend/src/stimulus/controllers/auto-theme-switcher.controller.ts b/frontend/src/stimulus/controllers/auto-theme-switcher.controller.ts
index 560d2c65822..241f8eab87a 100644
--- a/frontend/src/stimulus/controllers/auto-theme-switcher.controller.ts
+++ b/frontend/src/stimulus/controllers/auto-theme-switcher.controller.ts
@@ -41,7 +41,7 @@ export default class AutoThemeSwitcher extends Controller {
   declare readonly modeValue:string;
 
   connect() {
-    if (this.modeValue !== 'sync_with_system') return;
+    if (this.modeValue !== 'sync_with_os') return;
 
     useMatchMedia(this, {
       mediaQueries: {