Mammillaria geminispina, commonly named twin spined cactus, is a flowering plant in the family Cactaceae. It is native to central Mexico.
Mammillaria geminispina var. nobilis initially has a solitary growth habit, that may cluster over time. The cactus has white rounded tubercles (areoles), from which numerous whitish spines grow, which almost completely hide the green stem of the plant. It also has several longer and stronger, black-tipped spines. Flowering occurs only after the plant is seven to eight years old. It blooms with carmine red bell-shaped flowers.