Calvatia gigantea, commonly known as the giant puffball, is a puffball mushroom commonly found in meadows, fields, and deciduous forests usually in late summer and autumn. The large white mushrooms are edible when young.

Fruiting body shaped like a ball, or nearly so, white when fresh, becoming yellowish or olive brownish. The surface is less than 1 mm thick. soft, finely velvety when young, becoming bald. The inside of mature Giant puffballs is greenish-brown, whereas the interior of immature puffballs is white.

Similar species Bovista plumbea, which is a lot smaller.