Sibaropsis is a monotypic genus of flowering plants in the mustard family containing the single species Sibaropsis hammittii, which is known by the common name Hammitt's clay-cress. It is endemic to California, where it is known from two locations in the Peninsular Ranges. The plant is known from the Santa Ana Mountains of Riverside County and Viejas Mountain and nearby peaks east of San Diego. It grows in grassy habitat in openings in chaparral alongside purple needlegrass (Nassella pulchra), generally in moist areas in heavy clay soils. This species and its genus were first described to science in 1997.