Acmispon heermannii (formerly Lotus heermannii) is a species of flowering plant in the family Fabaceae known by the common names Heermann's bird's-foot trefoil and Heermann's lotus. It is native to the coastal plains, canyons, and mountains of California and Baja California, where it is known from several types of oceanside and inland habitat. It is a mat-forming perennial herb spreading straight stems along the ground. It is lined with leaves made up of several hairy oval leaflets. The inflorescence is a cluster of 3 to 8 flowers each up to about a centimeter long. The petals are yellow, often with dark lobes. The fruit is a curved, beaked legume pod.

The species was accepted by the Jepson eFlora as of 2012^[update],^[1] but regarded as the variety glabriusculus of Acmispon tomentosus by Plants of the World Online as of February 2021^[update].^[2]