Berberis microphylla, common name box-leaved barberry and Magellan barberry, in Spanish calafate and michay and other names, is an evergreen shrub, with simple, shiny box-like leaves. The calafate is native to southern Argentina and Chile and is a symbol of Patagonia.

The bush grows to a height of 1.0 to 1.5 m (3 ft 3 in to 4 ft 11 in). It has many arching branches, each covered in many tripartite spines. The bush has many small yellow flowers in summer. Its edible blue-black berries are harvested for jams, but are eaten fresh too - a legend tells that anyone who eats a calafate berry will be certain to return to Patagonia.

The calafate is grown commercially for its fruit, potential medical uses and as a garden plant or bonsai. Its wood is used to make a red dye. The cultivar Berberis microphylla 'Nana' is widely available as a garden shrub, and is also used in commercial plantings as a low spiny hedge to discourage intruders, but it does not fruit.

Berberis microphylla should not be confused with Mahonia microphylla, native to China.