Mammillaria spinosissima (), also known as the spiny pincushion cactus, is a species of flowering plant in the cactus family Cactaceae, endemic to the central Mexican states of Guerrero and Morelos, where they grow at elevations of approximately . The species was described in 1838 by James Forbes, gardener of the Duke of Bedford. Botanist David Hunt collected a specimen in 1971, when he located one near Sierra de Tepoztlan, Mexico.