USENIX is an American 501(c)(3) nonprofit membership organization based in Berkeley, California and founded in 1975 that supports advanced computing systems, operating system (OS), and computer networking research.

In June 1977, a lawyer from AT&T Corporation informed the group that they could not use the word "Unix" in their name as it was a trademark of Western Electric (the manufacturing arm of AT&T until 1995), which led to the change of name to USENIX.

As commercial interest grew, a number of separate groups started in parallel, most notably the Software Tools Users Group (STUG), a technical adjunct for Unix-like tools and interface on non-Unix operating systems, and /usr/group, a commercially oriented user group.

USENIX hosts numerous conferences and symposia each year, including: USENIX publishes a magazine called ;login: that appears four times a year.

[7] Since 2011, they have provided audio and video recordings of paper presentations and conference talks in their open-access materials, free of charge.