Windows 3.1x is a family of Windows versions following Windows 3.0 initially released in 1992. It added TrueType support and included multimedia components by default. System stability was greatly increased compared to Windows 3.0, while the user interface was refined and improved. Support for real mode was dropped, and in further updates, Standard mode was dropped as well. It was succeeded by Windows 95 released in 1995.

The first release was Windows 3.1 in 1992. Windows for Workgroups 3.1 was released alongside Windows 3.1 in 1992 and featured support for networking. It was updated to Windows for Workgroups 3.11 in 1993, whose core was also backported to Windows 3.1 as an update. A separate simplified-Chinese release called Windows 3.2 was also made, fixing problems related to the input of Chinese characters.