Short Answer: To enable dark mode on Firefox for Android: open the Firefox app → tap the three-dot menu → Settings → Customize → Dark. If you want dark mode on all websites too, install the Dark Reader add-on from Firefox’s add-on library.
How to Enable Dark Mode in Firefox for Android
Quick steps:
Open Firefox → tap ⋮ menu → Settings → Customize → Theme → Dark
- Open the Firefox app on your Android phone.
- Tap the three-dot menu (⋮) in the top-right corner.
- Tap Settings.
- Scroll down to Customize.
- Tap Theme and select Dark.
This changes Firefox’s interface — the address bar, tab bar, menus, and new tab page — to a dark theme. The change applies immediately.
📸 SCREENSHOT NEEDED: Screenshot: Firefox for Android Settings screen with Theme options showing Light / Dark / Follow device theme
Follow Device Theme (Automatic Dark Mode)
If you’ve already enabled dark mode at the Android system level and want Firefox to follow it automatically, select Follow device theme in the same Theme setting. Firefox will switch between light and dark to match whatever your Android system dark mode is set to — including any scheduled changes.
How to Enable Dark Mode on Websites in Firefox Android
Changing Firefox’s theme makes the browser interface dark, but websites themselves still load with their own colours — most will still be white/light unless you take an extra step.
For dark mode on websites, install the Dark Reader add-on:
- Tap the three-dot menu → Add-ons.
- Search for Dark Reader.
- Tap Add to Firefox.
Dark Reader applies a dark overlay to every website you visit. You can toggle it on/off for specific sites using the extension popup.
📸 SCREENSHOT NEEDED: Screenshot: Firefox Android Add-ons menu showing Dark Reader with the ‘Add to Firefox’ button
Firefox vs Chrome Dark Mode on Android — Which Is Better?
Chrome for Android follows the system dark mode automatically and applies it to web content too (via Chrome’s Force Dark Mode flag, or natively on Android 10+). Firefox’s approach is more controlled — you set it manually and can customise it per site with Dark Reader.
If you just want everything dark with no setup, Chrome + Android system dark mode is simpler. If you want fine-grained control over which sites go dark, Firefox + Dark Reader gives you more options.
Troubleshooting: Dark Mode Not Working in Firefox Android
Theme setting is grayed out
Update Firefox to the latest version from the Google Play Store. Older versions of Firefox Android had a different settings structure; the current version (Firefox for Android / Fenix) has the Theme option in Customize.
Websites still look white after enabling dark theme
Expected — the browser theme only changes Firefox’s own UI. Install Dark Reader to affect website colours.
Dark Reader is slowing down page loads
Dark Reader processes pages to invert and adjust colours, which adds a small overhead on complex pages. You can disable it on fast news sites and enable it mainly on apps and tools you spend a lot of time in. Tap the Dark Reader icon and use the site-specific toggle.
Quick checklist:
- ✅ Firefox app → ⋮ menu → Settings → Customize → Theme → Dark
- ✅ Use ‘Follow device theme’ to auto-switch with Android dark mode
- ✅ Install Dark Reader add-on to make websites dark too
- ✅ Dark Reader can be toggled per site from the add-on popup
Frequently Asked Questions
Does dark mode in Firefox save battery on Android?
On Android phones with AMOLED/OLED screens (most Samsung, Pixel, and OnePlus devices), dark mode does save meaningful battery because black pixels are powered off entirely. On LCD screens, the benefit is minimal. Given that most current flagship and mid-range phones use OLED, it’s worth enabling.
Can I schedule dark mode in Firefox Android?
Not directly within Firefox. Use Android’s built-in “Scheduled dark theme” (Settings → Display → Dark theme → Schedule) and set Firefox to “Follow device theme” — it will then switch automatically on your schedule.
Does Firefox for iOS also have dark mode?
Yes — Firefox on iPhone follows the same approach. Go to Settings → Theme → Dark, or choose Follow System Theme to match iOS’s dark mode setting.