Eschscholzia californica, the California poppy, golden poppy, California sunlight or cup of gold, is a species of flowering plant in the family Papaveraceae, native to the United States and Mexico. It is cultivated as an ornamental plant flowering in summer, with showy cup-shaped flowers in brilliant shades of red, orange and yellow. It is also used as food or a garnish. It became the official state flower of California in 1903.

The Papaveraceae are an economically important family of about 42 genera and approximately 775 known species of flowering plants in the order Ranunculales, informally known as the poppy family. The family is cosmopolitan, occurring in temperate and subtropical climates like Eastern Asia as well as California in North America. It is almost unknown in the tropics. Most are herbaceous plants, but a few are shrubs and small trees. The family currently includes two groups that have been considered to be separate families: Fumariaceae and Pteridophyllaceae. Papaver is the classical name for poppy in Latin.