Calochortus palmeri is a species of flowering plant in the lily family known by the common name Palmer's mariposa lily. It is endemic to California, where it is distributed mostly throughout the coastal mountain ranges from the Los Angeles area to the San Francisco Bay Area. It is a perennial herb producing a straight, branching stem up to 60 centimeters tall. The basal leaf is 10 to 20 centimeters long and withers by flowering. The flower cluster bears 1 to 6 erect, open bell-shaped flowers. Each flower has three brown-speckled sepals 3 centimeters long and three wider petals each 2 or 3 centimeters long. The petals are white to light lavender and have bases with yellow or purple hairs, or lacking hairs, depending on variety. There are two varieties of this species, the rarer of the two, Munz's mariposa lily (var. munzii), being known only from Riverside County.