Allium siskiyouense is a species of wild onion known by the common name Siskiyou onion. It is native to the Klamath Mountains and nearby ranges of northern California and southern Oregon, where it grows in serpentine and other rocky soil types. This small onion plant grows from a reddish brown bulb one or two centimeters long. It produces a short stem no more than 8 centimeters long and two sickle-shaped leaves which are usually longer. The inflorescence contains up to about 35 flowers, each with dark-veined pink tepals around a centimeter long and sometimes toothed at the tips.