Calochortus panamintensis is a species of flowering plant in the lily family known by the common name Panamint mariposa lily. It is endemic to Inyo County, California, where it is known only from the Panamint Range near Death Valley. Its range may technically extend just into Nevada. It is a perennial herb producing an unbranching stem 40 to 60 centimeters tall. The basal leaf is 10 to 20 centimeters long and withers by flowering, and there may be smaller leaves along the stem. The flower cluster bears 1 to 4 erect, bell-shaped flowers with three sepals and three petals each up to 4 centimeters long. The sepals may have dark spotting near the bases, and the white to pale purple flowers may have a red and yellow blotch at the base and green striping on the outer surfaces. The fruit is a narrow capsule about 7 centimeters long.