Coreopsis stillmanii is a species of flowering plant in the daisy family known by the common name Stillman's tickseed. It is endemic to California, where it grows in the Central Valley and most of the adjacent coastal and inland mountain ranges. This is an annual herb producing one or more erect stems with flower clusters growing to 30 centimeters in maximum height. The lobed, somewhat fleshy leaves are mostly located about the base of the plant and on the lower stem. The flower cluster bears a solitary flower head with a rounded involucre of green to reddish, rough-textured phyllaries. The flower head has a center of many yellow disc florets and a fringe of 5 to 8 yellow ray florets about a centimeter long on average. The fruit is an achene.