Firefox for iPhone no longer has an option called Night Mode. Its replacement is Website Dark Mode: tap the menu button at the bottom of the screen, then tap Turn on Website Dark Mode to darken the page you are reading. That is separate from Firefox’s Appearance (or Theme) setting, which only darkens Firefox’s own toolbars and menus, and from iPhone Dark Mode, which changes the whole phone.
Which dark setting do you need?
Older versions of the app had an Enable Night Mode item in the menu and a Display screen in Settings with a Dark choice. Mozilla now splits those jobs between two settings, and iOS adds a third. Pick the row that matches what you want to change:
| Setting | What turns dark | Where it is |
|---|---|---|
| Website Dark Mode | The web page itself: white backgrounds become dark | Firefox menu button > Turn on Website Dark Mode |
| Firefox Theme (Dark) | Firefox’s toolbars, menus, tab tray and Settings screens | Firefox menu > Settings > Appearance (or Theme in some versions) |
| iPhone Dark Mode | The Home Screen, Apple’s apps and other apps that support it | iPhone Settings > Appearance (on iOS 26 and earlier, Display & Brightness) |
For reading at night, you may want the first two together: dark pages inside a dark browser. The steps for each are below.
Turn on Website Dark Mode
Mozilla’s Website Dark Mode help page describes it as a way to invert web page colors to a dark theme, which can reduce eye strain in low light and potentially save battery life.
- Open the Firefox app and go to any web page.
Older iOS version shown; your Home Screen will look different.
- Tap the menu button at the bottom of the screen. On an iPad, the menu button is at the top right.
The menu button in an older version of Firefox for iOS.
- Tap Turn on Website Dark Mode. The page switches to dark colors right away. (Some of Mozilla’s pages call the same menu item Website dark mode, so look for either wording.)
The older Firefox menu, which had Enable Night Mode and Settings. Current versions show Turn on Website Dark Mode instead.
To turn it off, open the menu again and use the same item. Mozilla says repeating the steps returns the page to its original colors.
If a page looks odd in Website Dark Mode
Mozilla describes Website Dark Mode as inverting a page’s colors, so a page can look different from the way its site designed it. If a page is hard to read, turn Website Dark Mode off for a moment, then back on when you move to a text-heavy page. Some sites also offer their own dark design in their settings; where one exists, it may look better than the inverted page.
The Theme setting controls how the app looks around the page. Mozilla’s guide to changing themes in Firefox for iOS lists three ways it can work.
Mozilla’s help shows this screen under two names. Its dark theme page for Firefox for iOS has you tap the menu button, tap Settings, tap Appearance, and choose Light, Dark or Automatic; that screen also has a Website Dark Mode switch. If your Settings list shows Theme instead, use these steps:
- Tap the menu button, then tap Settings in the menu panel.
- In the General section, tap Theme.
The old layout: older versions had a Display item here. That screen no longer exists; current versions use Theme.
- Choose how Firefox picks light or dark:
- Use System Light/Dark Mode: on by default. Firefox follows your iPhone’s Dark Mode setting.
- Automatically: turn off the system option first, then choose this to switch between light and dark based on screen brightness. Adjust the brightness level under Threshold to set where it changes.
- Manually: turn off the system option, choose this, then pick Light or Dark under Theme Picker.
The Dark choice in an older version of Firefox for iOS. The current Theme screen is laid out differently.
Which to choose? If your iPhone already switches to Dark Mode at sunset, leave Use System Light/Dark Mode on and Firefox goes along with it. Choose Automatically if you want Firefox to darken when you lower the screen brightness in a dark room, and Manually with Dark if you want the browser dark all the time, even when the rest of the phone is light.
Keep in mind that the Theme setting alone does not change white web pages. Pair it with Website Dark Mode if the page itself is the problem.
Turn on Dark Mode for the whole iPhone
If you would rather have every app go dark, use iPhone Dark Mode. Apple’s Dark Mode article gives these steps:
- Open the Settings app and tap Appearance. On iOS 26 and earlier, tap Display & Brightness instead.
- Select Dark.
- Optional: select Automatic, then tap Options to set a schedule.
For a quicker switch, open Control Center, touch and hold the brightness bar, and select Dark Mode. With Firefox’s Theme left on Use System Light/Dark Mode, the browser follows along.
For pages or apps that stay bright even then, the iPhone’s accessibility options can help. Smart Invert reverses colors across the screen while leaving images alone; see how to invert colors on an iPhone for the steps and the triple-click shortcut.
Turn dark mode off again
- Dark web pages: open the Firefox menu and tap the Website Dark Mode item again.
- Dark Firefox menus: go to Settings > Appearance and choose Light or Automatic; if you see Theme instead, turn Use System Light/Dark Mode back on or choose Manually and Light.
- Dark iPhone: go to Settings > Appearance (or Display & Brightness) and select Light.
Firefox dark mode questions
Is Website Dark Mode the same as Night Shift?
No. Night Shift is an iPhone display setting that shifts the screen toward warmer colors, while Website Dark Mode changes the colors of the page. You can use both at once. See where to find the iPhone’s blue light filter for Night Shift.
Do other browsers and apps work the same way?
Each app has its own setting, and the names differ. For example, here is how to switch the Microsoft Edge iPhone app to dark mode, and how to get the dark screen in the YouTube app.
A site still misbehaves after I change these settings. What else can I try?
Display settings don’t affect stored site data. If a page won’t load correctly or keeps showing old content, clearing cookies in the Firefox iPhone app is a common next step.
Kermit Matthews runs Live2Tech from just outside Philadelphia. He is an IT specialist with over 20 years of experience, from a university help desk to small-business IT, IT management and his own consulting practice, and has written tech guides full time since 2020. Steps are checked against the current software on a real device or the maker’s official documentation. More about Kermit.