Harpastum, also known as Harpustum, was a form of ball game played in the Roman Empire. The Romans also referred to it as the small ball game. The ball used was small (not as large as a follis, paganica, or soccer-sized ball) and hard, probably about the size and solidity of a softball. The word harpastum is the latinisation of the Greek ἁρπαστόν (harpaston), the neuter of ἁρπαστός (harpastos), "carried away", from the verb ἁρπάζω (harpazo), "to seize, to snatch".

This game was apparently a romanized version of a Greek game called phaininda (Greek: φαινίνδα), or of another Greek game called ἐπίσκυρος (episkuros). It involved considerable speed, agility, and physical exertion. Little is known about the exact rules of the game, but sources indicate the game was a violent one with players often ending up on the ground. In Greece, a spectator (of the Greek form of the game) once had his leg broken when he got caught in the middle of play.

The general impression from these descriptions is of a game quite similar to rugby. Additional descriptions suggest a line was drawn in the dirt, and that the teams would endeavor to keep the ball behind their side of the line and prevent the opponents from reaching it. This seems rather like an 'inverted' form of football. If the opponents had the ball on their side of the line, the objective would seem to be to get in and "pass" it to another player, or somehow get it back over the line.