The Cactaceae is a monograph on plants of the cactus family written by the American botanists Nathaniel Lord Britton and Joseph Nelson Rose and published in multiple volumes between 1919 and 1923. It was landmark study that extensively reorganized cactus taxonomy and is still considered a cornerstone of the field. It was illustrated with drawings and color plates principally by the British botanical artist Mary Emily Eaton as well as with black-and-white photographs.

Nathaniel Lord Britton was an American botanist and taxonomist who co-founded the New York Botanical Garden in the Bronx, New York.