Stachys harkerae sp. nova from western Mexico is characterized by its indumentum on stems, leaves and inflorescences composed of tiny glandular-capitate hairs, hirsute stems, and calyces relatively long-toothed surrounding corolla tube, which is rose to pale rose-orangish, exannulate inside and with the tube 6.7–8.2 mm long. Stachys harkerae is most similar to S. bigelovii but differs in having profusely hirsute stems, slightly larger leaves, shorter corolla tubes and a shorter lower corolla lip. It also differs in distribution and habitat; Stachys harkerae is adapted to wetter and warmer conditions below 1450 m a.s.l., whereas S. bigelovii occupies xeric environments, usually above 2200 m a.s.l. An identification key to Stachys in western Mexico is provided.