Steve Jackson Games (SJG) was founded in 1980 by Steve Jackson following his acquisition of The Space Gamer magazine. Products include card games, strategy games, board games, role-playing games, and periodicals, including Car Wars, Killer, Ogre, Illuminati, Munchkin, GURPS, and Pyramid.

SJG originally started producting microgames (in ziplock bags or plastic cases), but GURPS became the main product line after it's release in 1985 and hundreds of genre and setting worldbooks were produced. Munchkin, a parodic card game inspired by the Third Edition of Dungeons & Dragons became a runaway success and has been the company's primary money-maker for a number of years.

The most significant event in the history of SJG is probably the 1990 raid by the Secret Service. The reasons behind the raid are murky, but SJG was led to believe the target Loyd Blankenship's GURPS Cyberpunk manuscript, though it may be related to an e911 file from Bell South. Most of the confiscated files were returned three months later and no charges were ever filed, but the raid almost drove SJG into bankruptcy. SJG won two of three counts in their subsequent lawsuit, and the case was an impetus behind the creation of the Electronic Frontier Foundation and the Hacker game.

In February 2008, Steve Jackson set aside operational responsibilities for the company, and appointed Philip Reed (of Ronin Arts) Chief Operational Officer.