Thelypodium cooperi S.Watson(basionym)[2] Caulanthus cooperi is a species of flowering plant in the family Brassicaceae known by the common name Cooper's wild cabbage.

It is native to the southwestern United States and Baja California, where it is a common plant in a number of open, sandy habitats.

This annual herb produces a slender, somewhat twisted stem with widely lance-shaped to oblong leaves clasping it.

The flower has a rounded or urn-shaped coat of pinkish or pale greenish sepals enclosing light yellow or pale purple petals.

The fruit is a straight or curving silique several centimeters long.