Deinandra minthornii (syn. Hemizonia minthornii), and known by the common names Santa Susana Tarplant or Santa Susana Tarweed, is a rare California native species of flowering plant in the Aster family.
It is endemic to western Los Angeles County and eastern Ventura County, in the Santa Susana Mountains, Simi Hills, and Santa Monica Mountains. They are part of the western Transverse Ranges region in Southern California.

This plant grows in the Coastal sage scrub and Chaparral habitats of the California Coastal Sage and Chaparral ecoregion, and the Chaparral habitat of the inland adjacent California Montane Chaparral and Woodlands ecoregion. It can be found on rocky outcroppings and in sandstone crevices, from 980 to 1,640 feet (300-500 m) in elevation.

Santa Susana Tarplant is a shrub or subshrub growing 5.9 inches to 3.3 feet (15 cm-1 m) in height. The stems are hairy, glandular, and leafy. The thick leaves are linear, smooth-edged or with a few teeth, and are glandular and hairy to bristly. The phyllaries lining the flower heads are coated in glands. The head contains four to eight yellow ray florets and several yellow disc florets.

Deinandra minthornii is an endangered species, listed as a Threatened Species by the California State Department of Fish and Game, as an Imperiled Species under the California Endangered Species Act-CESA, and is on the California Native Plant Society Inventory of Rare and Endangered Plants of California. There are about 20 occurrences/populations of the plant, but several have not been observed recently.