Achnatherum lemmonii is a species of grass known by the common name Lemmon's needlegrass. It is native to western North America, where its distribution extends from British Columbia to southern California. This perennial grass forms a dense clump of stems up to 90 centimetres (35 in) tall. It may be hairless, hairy, or woolly. The inflorescence is a panicle up to 21 centimetres (8.3 in) long by 1 centimeter wide. The spikelets may be over 1 centimetre (0.39 in) long. The awns are up to 3 centimetres (1.2 in) long.