Lieutenant Simon "Ghost" Riley was a British special forces operator in Call of Duty: Modern Warfare 2, Modern Warfare 2: Ghost,Call of Duty: Online, Find Makarov: Operation Kingfish and Call of Duty: Heroes. He also appears as a customization option in Call of Duty: Ghosts.

Ghost was first seen in the original Call of Duty: Modern Warfare title and has been featured in every game in the Modern Warfare series since then. He was a playable character in the original Modern Warfare 2 but only in multiplayer modes. In the new Modern Warfare 2, he is one of the three playable protagonists.