UnixWare is a Unix operating system. It was originally released by Univel, a jointly owned venture of AT&T's Unix System Laboratories (USL) and Novell. It was then taken over by Novell. Via Santa Cruz Operation (SCO), it went on to Caldera Systems, Caldera International, and The SCO Group before it was sold to UnXis. UnixWare is typically deployed as a server rather than a desktop. Binary distributions of UnixWare are available for x86 architecture computers. UnixWare is primarily marketed as a server operating system.

Unix System Laboratories (USL), sometimes written UNIX System Laboratories to follow relevant trademark guidelines of the time, was an American software laboratory and product development company that existed from 1989 through 1993. At first wholly, and then majority, owned by AT&T, it was responsible for the development and maintenance of one of the main branches of the Unix operating system, the UNIX System V Release 4 source code product. Through Univel, a partnership with Novell, it was also responsible for the development and production of the UnixWare packaged operating system for Intel architecture. In addition it developed Tuxedo, a transaction processing monitor, and was responsible for certain products related to the C++ programming language. USL was based in Summit, New Jersey, and its CEOs were Larry Dooling followed by Roel Pieper.