How to Turn on Dark Mode in Firefox

Mozilla Firefox has a dark theme. Learn how to turn on the dark theme in Firefox and use it on every website you visit.
Warp Terminal

Operating systems, applications, and web pages are adding support for the dark mode (or dark theme/night theme) to help people reduce eye strain.

You can enable the dark mode with Mozilla Firefox in various ways.

Here, I shall highlight the methods to enable the dark mode theme on your browser and solutions to turn the websites to use dark mode.

Enable dark mode in the Mozilla Firefox web browser

There are two methods to enable dark mode for your web browser. Let’s take a look at it:

1. Using Firefox Default Theme

Note that this aims to enable the dark mode theme for the browser. It does not affect the websites you browse.

Step 1: In Firefox, go to the top-right corner and open the menu by clicking the hamburger menu and then click on the “Add-ons” menu entry.

You could also use the Ctrl+Shift+A keyboard shortcut. On the “Add-ons” page, you will see a list of the extensions that you have installed or disabled.

access addons and themes
Add-ons and Themes in the Menu

On the “Add-ons” page, you will see a list of the extensions that you have installed or disabled.

Step 2: Now, we need to switch to the themes page. You can do that by clicking “Themes” on the left side of the screen.

2 theme select
Dark Theme Select and Enable

You will see the “Dark” theme. Click on the “Enable” button to immediately activate the dark mode for the browser.

Note: If you have Firefox Sync turned on, dark mode will be activated on all your Firefox installs.

As an alternative to this, you can also select the dark theme for the browser through general settings, as shown below:

2. firefox dark option 1

It is essentially the same and could be a quick way to toggle the theme of your browser.

2. Using Firefox Colors Extension

If you need more control and customization to enable the dark mode for every inch of your browser, the ‘Firefox Color‘ browser add-on should come in handy. Again, it is only meant for the browser, not the websites you visit.


You just have to head to its extension page and add it to the browser. In case you didn’t notice, it is an extension by Mozilla Firefox, so you should be good to go.

It provides a wide selection of colors and lets you customize various aspects of the browser. You also get a live preview of the changes you make.

7 firefox colors tweaks
Firefox Colors Tweaks

Enable a dark theme for the websites in Firefox with Dark Reader

While it is good to have dark mode enabled for the browser, it may or may not make a big difference if the web pages cause eye strain.

That would be inconvenient, won’t it?

If you want to turn on dark mode for all the websites you visit, you can install the Dark Reader extension.

If you’re curious, Dark Reader happens to be one of the best open-source add-ons available for Mozilla Firefox.

The extension is also available for Chrome and Safari.

You can get the Dark Reader add-on for Firefox from its extension page. Just click on the Add to Firefox button to add this extension.

3 dark reader extension
Dark Reader Extension in Firefox

You may/may not need to restart Firefox to see the changes into effect. Here’s a screenshot of It’s FOSS homepage with Dark Reader:

4 itsfoss in dark mode
It’s FOSS Page in Dark Mode with Dark Reader

Dark Reader also provides you with options to set the intensity level of darkness, accent color, etc. You can turn off dark mode on selected websites.

5 dark reader settings
Dark Reader customization options

It makes much more sense to use Dark Reader with its customizability over a website’s dark mode toggle.

You can enjoy the dark mode on Firefox entirely now. If you are using Chromium on Linux, you should also be able to use the Dark Reader extension.

11 Best Firefox Extensions to Improve Browsing Experience
Use these Firefox add-ons to step up your browsing experience!

More Firefox tweaking

In another quick Firefox tip, you may learn about removing the title bar from Firefox to save some screen space.

How to Remove Title Bar From Firefox and Save Screen Space
Firefox has a tab at the top that displays the information about active tabs, taking extra screen space. Learn to remove title bar from Firefox.

Not my favorite but I know some people like using the backspace key to go back to previous page.

How to Enable Backspace in Firefox [Quick Tip]
Want to use the backspace key to go back to the previous page in Mozilla Firefox? Here’s how to enable backspace in Firefox.

Use an extension to watch Netflix in HD on Firefox in Linux.

Watch Netflix in Full HD on Firefox
Paying for full HD streaming to Netflix and yet it doesn’t play in 1080p? Here’s how you can make Netflix play full HD on Firefox browser.

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About the author
John Paul Wohlscheid

John Paul Wohlscheid

My name is John Paul Wohlscheid. I'm an aspiring mystery writer who loves to play with technology, especially Linux. You can catch up with me at:

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