Which company created the Windows operating system?

Microsoft created the Windows operating system.

Microsoft announced Windows in 1983 as a graphical operating environment intended to run with MS-DOS. Windows 1.0 was released in 1985, and later versions gradually became full operating systems with their own broader hardware and software ecosystems.

Windows became one of the world’s dominant desktop-computing platforms, helped by widespread adoption in homes, schools, and businesses. Major releases included Windows 95, Windows XP, Windows 7, and Windows 10.

A common mix-up concerns IBM. IBM supplied important personal computers and partnered with Microsoft on early software, but Microsoft developed Windows. Windows is also separate from Microsoft’s server products and from the Xbox operating system, although they share technology in some areas.