Armored Core: Master of Arena[a] is a video game for the PlayStation. Master of Arena is the third entry in the Armored Core series and a direct sequel to Armored Core: Project Phantasma.

The story follows a survivor whose family was lost in a battle. The survivor joins the Raven's Nest to pilot an Armored Core unit through the dangerous Arena in an attempt to confront the top pilot, Hustler One, and kill him for his role in that battle. While fighting to reach the top, the survivor finds allies in the form of his or her manager, Lana Nielsen, and sponsor, Elan Cubis, both of whom have their own agendas.

The gameplay is largely identical to the previous two Armored Core games, but places a larger focus on the Arena feature that was introduced in Project Phantasma. Players can import their saved characters from either of the earlier Armored Core games to retain their customization and gain an advantage in Master of Arena. A newly-added "Ranker MK" mode gives players control over custom opponents that they can then fight in the Arena