The California Poppy (Eschscholzia californica) is a popular garden flower of the family Papaveraceae. It is native to California and the southwestern United States. It was named by the German romantic poet and explorer Adelbert von Chamisso after his friend and colleague on the Otto von Kotzebue scientific expedition to California in the early 19th century, the Baltic German Johann Friedrich von Eschscholtz.

Each plant will branch into many stems, each with a single, four-petaled yellow or orange bloom about 2 inches wide. It is drought tolerant and easy to grow; seeds and seedlings are sold commercially in other places with suitable climate, such as parts of Australia. It readily naturalizes (reseeds).

Horticulturalists have produced strains with various other colors and blossom and stem forms. These typically do not breed true on reseeding.

This plant is the state flower of California, where it may readily be seen in the spring and early summer in many parts of the state.

A common myth is that it is illegal to cut or otherwise damage California poppies just because it is the state flower. There is no such law. There is a state law that makes it a misdemeanor to cut or remove any flower, tree, shrub or other plant growing on state or county highways (with an exception for authorized government employees and contractors).

Poppy seeds are often used in salads or on baked goods. Poppy seed pollen was once used cosmetically by Native Americans.

The Antelope Valley California Poppy Reserve is located in northern Los Angeles County, California. At the peak of their blooming season orange petals seem to cover all 1,745 acres (7 km²) of the reserve.

California Poppy in early March.

The California poppy is featured on the state's official welcome signs.