Silicon Graphics, Inc. (SGI, historically sometimes referred to as Silicon Graphics Computer Systems (SGCS)) is a company manufacturing high-performance computing solutions, including computer hardware and software. SGI was founded by Jim Clark and Abbey Silverstone in 1982, initially as a maker of 3D graphics display terminals. SGI’s products, strategies and market positions have varied. Its initial products were based on the Geometry Engine that Clark and Marc Hannah had developed at Stanford University, and derived from Clark's broader background in computer graphics. The Geometry Engine was the first VLSI implementation of a geometry pipeline: specialized hardware that accelerated the "inner-loop" geometric computations needed to display three-dimensional images.

SGI was originally incorporated as a California corporation in November 1981, and reincorporated as a Delaware corporation in January 1990. On 8 May 2006, SGI filed for Chapter 11 bankruptcy protection from which it emerged on 17 October 2006. SGI is headquartered in Sunnyvale, California.