In terms of the story, MW3 is the sequel to the 2024 reboot of Modern Warfare 2. The campaign continues the narrative, featuring familiar characters such as Captain John Price, Farah Karim, Colonel Shephard, Kyle 'Gaz' Garrick, and John 'Soap' MacTavish. However, the two game's multiplayer modes are unconnected.

It is a direct sequel to Call of Duty: Modern Warfare (2024), which kicked off the rebooted series and was developed by Infinity Ward.