A new species of Cypraeidae is described from the middle Campanian (Late Cretaceous) portion of the Schulz Ranch Member of the Williams Formation, Santa Ana Mountains, Orange County, southern California. This is the first cypraeid described from the Williams Formation and only the second cypraeid species described from the Santa Ana Mountains. New paleogeographic and chronologic records of previously described and indeterminate Cretaceous cypraeid species are also listed.