Dynix (short for DYNamic unIX) is an operating system developed by Sequent. It is a flavor of Unix based on BSD. DYNIX was replaced by DYNIX/ptx , which was based on the System V version of UNIX produced by AT&T.

Another use of the term Dynix refers to a company and to one of their older software products. Dynix Corporation is a software company that develops software for libraries (e.g. public libraries, academic libraries, etc.) The company's legacy product which was first developed on mainframe systems is also known as Dynix, and is still widely used in libraries throughout the world. Dynix Corporation obtained the trademark for the term 'Dynix' from IBM in 2001.