Atriplex gypsophila R.E.Preston is a newly described species that grows on gypsum-rich clay barrens in the Ciervo Hills in central western California. It is morphologically most similar to Atriplex coronata S.Watson and Atriplex vallicola Hoover, but differs from these species by the size and shape of the leaves and diaspores and by the clay barrens or badlands habitat preference, in contrast to the alkali soil habitats where most other annual Atriplex in and adjacent to California's Great Valley occur. Atriplex gypsophila is rare by virtue of its limited distribution and habitat fidelity and merits recognition as a species of conservation concern. Atriplex gypsophila is compared with A. coronata and A. vallicola, two species with which it could be confused, and illustrations of all three species are provided.