How to stop Firefox from changing to dark or light theme automatically on Windows 10

If Firefox keeps changing themes automatically on Windows 10, then use this guide to stop it.

Mozilla Firefox theme settings on Windows 10
Mozilla Firefox theme settings on Windows 10

When you switch to the light or dark theme on Windows 10, supported apps also switch their mode to align with the color with the rest of the environment.

Although Firefox isn’t an app available from the Microsoft Store, it’s been updated to automatically follow the color theme you set on Windows 10. However, if you want Firefox to use a specific theme color no matter the mode you use in the operating system, you can quickly accomplish this by changing the browser settings.

In this guide, you’ll learn the steps to set a permanent default color theme on Firefox to prevent the browser from changing colors when you switch to light or dark mode on Windows 10.

How to set default theme for Firefox

If you want to prevent Firefox from changing the theme color to align with the color mode you set on Windows 10, use the following steps:

  1. Open Firefox.

  2. Click the menu (hamburger) button on the top-right corner.

  3. Click the Customize option.

    Firefox main menu
    Firefox main menu
  4. Select the theme (Light or Dark) that you want to use.

    Firefox theme settings
    Firefox theme settings

Once you’ve completed the steps, Firefox will remember your settings, and it won’t change it the next time you change your system color theme.

If you want to revert the changes, you can use the same instructions outlined above, but on step No. 4, make sure to select the Default option.

About the author

Mauro Huculak is a Windows How-To Expert who started Pureinfotech in 2010 as an independent online publication. He has also been a Windows Central contributor for nearly a decade. Mauro has over 15 years of experience writing comprehensive guides and creating professional videos about Windows and software, including Android and Linux. Before becoming a technology writer, he was an IT administrator for seven years. In total, Mauro has over 21 years of combined experience in technology. Throughout his career, he achieved different professional certifications from Microsoft (MSCA), Cisco (CCNP), VMware (VCP), and CompTIA (A+ and Network+), and he has been recognized as a Microsoft MVP for many years. You can follow him on X (Twitter), YouTube, LinkedIn and Email him at [email protected].