Firefox dark mode can change the browser interface, signal a dark color preference to compatible websites, or apply a darker appearance to webpages. These are separate settings, and changing Firefox’s theme does not guarantee that every website will become dark.
This guide shows you how to turn on Firefox dark mode on desktop, Android and iOS. It also explains how to use Night Eye when you want a consistent, customizable dark theme across websites.
Last reviewed: August 2026.
Firefox Dark Mode: Quick Answer
| What you want to darken | Recommended option |
|---|---|
| Firefox toolbars, menus and built-in pages | Enable Firefox’s Dark theme |
| Compatible websites | Set Website appearance to Dark |
| Websites that remain bright | Use a Firefox dark-mode extension |
| Firefox interface on Android | Settings → Customize → Theme → Dark |
| Websites in Firefox for iOS | Menu → Turn on Website Dark Mode |
Important: A dark Firefox theme and a dark website are not the same thing. Some sites follow the browser’s requested color scheme, while others require their own setting or a browser extension.
Table of contents
- Firefox Dark Mode: Quick Answer
- Browser Theme vs. Website Dark Mode
- How to Turn On Firefox Dark Mode on Desktop
- How to Make Websites Dark in Firefox
- How to Force Dark Mode on Websites in Firefox
- How to Turn On Firefox Dark Mode on Android
- How to Turn On Firefox Dark Mode on iPhone and iPad
- What to Do If Firefox Dark Mode Is Not Working
- How to Turn Off Firefox Dark Mode
- When Firefox Dark Mode Is Useful
- Frequently Asked Questions
- Get Customizable Dark Mode in Firefox
Browser Theme vs. Website Dark Mode
Firefox provides more than one appearance control. Choose the setting that matches what you want to change.
Firefox browser theme
The Firefox browser theme changes the interface around a webpage, including tabs, toolbars, menus and built-in pages. Mozilla notes that some websites may also respond to the selected theme, but this is not guaranteed.
Use this option when your main goal is to make Firefox itself dark. See Mozilla’s guide to changing Firefox themes.
Website appearance
Website appearance tells compatible websites which color scheme you prefer. Firefox can request Dark, Light or Automatic behavior. The website still controls whether and how it responds.
Use this option when you want supported sites to display their own dark design. Mozilla explains the available choices in its Website appearance guide.
Night Eye extension
Night Eye is a dark mode extension for Firefox that processes webpage colors when a site does not provide a suitable dark theme. It is the better fit when you want adjustable brightness, contrast, saturation, warmth, dimming and separate settings for individual websites.
Night Eye can also follow your system color scheme or a schedule. Page analysis and color conversion happen locally on your device, and Night Eye does not collect your browsing history.
How to Turn On Firefox Dark Mode on Desktop
These steps change Firefox’s toolbars, menus and built-in pages on Windows, macOS and Linux:
- Open Firefox.
- Select the menu button in the upper-right corner.
- Select Add-ons and themes. Some versions label this option Extensions and themes.
- Select Themes.
- Find Dark and select Enable.
The browser interface should change immediately. This does not force every open website to use dark colors.
How to Make Websites Dark in Firefox
To request dark mode from compatible websites in Firefox on a computer:
- Open the Firefox menu and select Settings.
- Open the General panel.
- Find Website appearance under the appearance settings.
- Select Dark.
- Reload any open website that does not update immediately.
Dark asks websites to use a dark color scheme. Light requests a light scheme, while Automatic lets the browser follow the relevant Firefox or system appearance behavior.
If a site has its own theme control, that setting may take priority. For example, some services offer an account-level appearance menu, while sites such as Google Docs or Amazon may need a different method depending on the platform.
How to Force Dark Mode on Websites in Firefox
Firefox’s Website appearance setting can request a dark color scheme, but websites control how they respond. If a site remains bright, a Firefox extension such as Night Eye can process the page and apply a dark appearance.
- Add Night Eye to Firefox.
- Open or reload the website you want to make dark.
- Select the Night Eye icon in the Firefox toolbar.
- Use Dark mode for full color conversion, or Filtered mode to keep the site’s colors while adjusting brightness, contrast, warmth and dimming.
- Apply the settings globally or only to the current website.
Night Eye works on most conventional websites, but Firefox-protected pages, browser settings, local files and unusual website designs may not be modifiable. If one website does not render as expected, use its individual settings or report it through Night Eye’s built-in support.
How to Turn On Firefox Dark Mode on Android
To change the Firefox app interface on Android:
- Open Firefox.
- Tap the three-dot menu button.
- Tap Settings.
- Under General, tap Customize.
- Under Theme, select Dark.
You can also select Follow device theme if you want Firefox to match Android’s appearance. Mozilla documents these options in its current Firefox for Android theme guide.
This setting changes the Firefox app interface. It does not guarantee that webpages will become dark. For a bright website, check whether the site has its own theme or use Night Eye in Firefox for Android. See the full guide to Firefox dark mode on Android.
How to Turn On Firefox Dark Mode on iPhone and iPad
Change the Firefox app theme
To make the Firefox app interface dark:
- Open Firefox on your iPhone or iPad.
- Tap the menu button. On iPad, the menu appears in the upper-right corner.
- Tap Settings.
- Tap Appearance.
- Select Dark. Choose Automatic if you want Firefox to adjust automatically.
Turn on Website Dark Mode
Firefox for iOS also has a separate control for webpages:
- Open the webpage you want to darken.
- Open the Firefox menu.
- Tap Turn on Website Dark Mode.
You can also manage Website Dark Mode from the Appearance settings. Use the same menu action to turn it off. This feature changes webpage colors and is separate from the Firefox app theme. See Mozilla’s Website Dark Mode instructions for iOS.
What to Do If Firefox Dark Mode Is Not Working
If Firefox dark mode is missing, inconsistent or not affecting the page you expected, work through these checks:
- Confirm whether you changed the Firefox theme or the separate Website appearance setting.
- Reload the website after changing an appearance setting or installing an extension.
- Check whether the website has its own theme control and whether it overrides the browser preference.
- Confirm that Night Eye is enabled and allowed to run on the affected website.
- Check whether the page is a protected Firefox page, a browser settings page or a local file.
- Temporarily disable other appearance extensions that may conflict with Night Eye.
- Update Firefox and Night Eye to their current versions.
- If only one website is affected, adjust Night Eye’s settings for that site rather than changing your global setup.
- On Android, confirm whether you are changing the app interface or trying to change webpage colors.
How to Turn Off Firefox Dark Mode
Reverse the same setting you used to enable dark mode:
- Firefox desktop theme: Open Menu → Add-ons and themes → Themes, then disable Dark or enable the System or Light theme.
- Website appearance on desktop: Open Settings → General → Website appearance, then choose Light or Automatic.
- Night Eye: Open the extension and choose Normal mode, disable it for the current site, or turn off the extension from Firefox’s Extensions panel.
- Android app: Open Settings → Customize → Theme, then choose Light or Follow device theme.
- Firefox for iOS: Change the app appearance to Light or Automatic. For webpages, open the menu and tap Turn off Website Dark Mode.
When Firefox Dark Mode Is Useful
Dark mode is mainly an appearance choice. It can be useful when you want:
- Less glare from large white backgrounds in a dim room.
- A browser and website appearance that matches your personal preference.
- Potentially lower display power use on an OLED screen, depending on the colors, brightness and device.
A converted page can sometimes have weak contrast or colors that are harder to read. If that happens, adjust the site’s brightness and contrast, switch modes, or return that page to its original appearance.
Frequently Asked Questions
Does Firefox have a built-in dark mode?
Yes. Firefox has a Dark theme for its browser interface. Desktop Firefox also has a Website appearance preference for compatible sites, while Firefox for iOS provides a separate Website Dark Mode action.
Why is a website still white when Firefox uses the Dark theme?
The Firefox theme primarily changes the browser interface. A website may ignore the browser’s color preference, use its own saved theme or lack a dark design.
How do I force dark mode on websites in Firefox?
First set Website appearance to Dark. If a website stays bright, Night Eye can apply a dark conversion to most regular webpages. Protected Firefox pages and some unusual designs may remain unchanged.
Can I use Night Eye with Firefox for Android?
Yes. Night Eye supports Firefox for Android. Install it through Firefox’s add-on system, reload the website and open the extension from the Firefox menu to manage the page.
Does Firefox for iPhone and iPad darken websites?
Firefox for iOS includes Website Dark Mode. Open the menu and select Turn on Website Dark Mode. This is separate from the app’s Light, Dark and Automatic appearance options.
Does Firefox dark mode save battery?
Dark pixels can use less power on some OLED displays. Actual savings depend on the screen, brightness, colors and how long dark content is displayed.
Get Customizable Dark Mode in Firefox
If Firefox’s native settings leave some websites bright, Night Eye can apply a darker appearance and let you adjust each site separately. You can also change brightness, contrast, saturation, warmth and dimming without changing the website for anyone else.