The human cannonball is a performance in which a person (the "cannonball") is ejected from a specially designed cannon. The impetus is provided not by gunpowder, but by either a spring or jet of compressed air. In a circus performance, gunpowder may be used to provide visual and auditory effects, but this is unrelated to the launching mechanism.

The human cannonball lands on a horizontal net or inflated bag, the placement of which is determined by classical mechanics. Outdoor performances may also aim at a body of water.