An American company developing games in the Halo series since 2007. Located in Redmond, Washington. The studio was named after the character 343 Guilty Spark from the same series of games.
Pred nekaj leti po izdaji Halo 5: Guardians je eden izmed razvijalcev potrdil, da je bil računalniški port resnično v Microsoftovih načrtih. Vendar je bil kasneje preklican zaradi težav z implementacijo.