Beginning with version 91, Firefox lets you login to Microsoft, Work, and School sites using Windows 10 Single Sign-On. Mozilla added an SSO preference to Firefox 91 Settings to make that possible, all you need to do is select the pref checkbox.
What is Single Sign-On (SSO)
Many organizations, enterprises, and even individuals need to repeatedly type their usernames and passwords to access multiple applications.
Single Sign-on avoids this hassle by allowing to use of a single set of login credentials for all the apps where several logins are required.
Microsoft Edge Chromium already supports SSO, Chrome to offer a Pref for the same, now Firefox joining these.
If you’re using new Edge, open Settings and visit the Profiles section to notice Edge offering a Setting named “Allow single sign-on for work or school sites using this profile”.

If the setting is enabled, you can access school or work sites on the Windows device using the profile.
If disabled, you need to switch to respective account profiles for a single sign-on.
The Firefox pref we going to give below works the same way as well.
The Pref is currently available out of the box in Beta Settings without the need to delve into about:config.
Enable Sign Sign-on for Firefox 91 on Windows 10
- Launch Firefox browser
- Click on Menu
- Select Settings
- Visit Privacy and Security > Logins and Passwords
- Enable or check the “Allow Windows Single Sign-on ” Setting.

As of now, Mozilla wants to offer SSO pref in Firefox for Windows 10 only.
if the feature adoption increases, then the company may make it available for other Windows versions also.
According to the Firefox Release schedule, Firefox 91 is scheduled to arrive on September 10.
Let us hope the SSO UI setting makes it into Release.
What’s your take on this? Will you find it useful? Let us know in the comments below?
More on Firefox:
Firefox Proton Redesign removes Page Actions Menu
How to Enable Compact density option in Firefox 89
Seamlessly switch between profiles in Firefox from the toolbar
Firefox on Android to Autofill Credit Card data and addresses