Nasturtium gambellii is a rare species of flowering plant in the mustard family known by the common names Gambel's yellowcress and Gambel's watercress. It is known from three or four scattered occurrences in California. It has been reported to exist in central Mexico and Guatemala, but these reports remain unconfirmed and in need of further investigation. Its total U.S. population was last estimated at fewer than 300 individuals. It was federally listed as an endangered species of the United States in 1993.