Allium elmendorfii is a species of wild onion endemic to Texas. It is known only from Bexar, Frio, Wilson, and Atascosa Counties. It is generally found on sandy soils. Allium elmendorfii is a bulb-forming herb with clusters of small bulbils around the roots, but without the dry papery outer layers that the domesticated onions have. It has an umbel of 10-30 erect to spreading flowers, each with 6 white to pinkish tepals about 5 cm (2 inches) long.