Marcus could refer to the following:
- Marcus (Day 2) - racist who attacked Yusuf Auda and Kate Warner from Season 2
- Marcus (Day 6) - man who was contracted to build a suitcase nuke component for terrorist Abu Fayed from Season 6
- Marcus (Day 10) - one of the members of Isaac Carter's gang from 24: Legacy.
- Marcus Alderbrook - senator briefly seen in Season 7
- Marcus Alvers - terrorist employed by Stephen Saunders to spread the Cordilla virus from Season 3
- Marcus Holt - highly placed CTU operative who was assassinated in China prior to 24: Day 6 Debrief
- Marcus Johnson - rogue CTU agent in 24: Countdown