Caulanthus major is a species of flowering plant in the family Brassicaceae known by the common name slender wild cabbage.

It is native to the Great Basin and surrounding regions of the United States, where it grows on dry mountain slopes and similar habitat.

It is a perennial herb growing an erect, hollow stem from a woody caudex.

The largest leaves are lowest on the stem and may reach 9 centimeters long.

The flower is enclosed in thick, sometimes hairy sepals which are very dark in color when new, usually a deep purple.