Richard Clifford Diebenkorn, Jr. (April 22, 1922 - March 30, 1993) was a well-known 20th century American painter.

Diebenkorn was born in Portland, Oregon; his family moved to San Francisco, California when he was two. In 1940, Diebenkorn entered Stanford University.

He lived in Berkeley, California from 1955 to 1967 and painted and drew in a representational style. At the time, Abstract Expressionism had captured attention in New York, and brought the focus of painting over to the US from France. Painting on the West Coast, however, retained independence from New York. Diebenkorn, Elmer Bischof , David Park, and later, Joan Brown , Manuel Neri , and Nathan Oliviera retained an interest in the figurative.

His most famous paintings, the "Ocean Park" series of works, were began in 1967 and developed over twenty years in over 140 paintings. They were aerial landscape abstracts named after a community in Santa Monica, California, where he had moved to teach at UCLA.

He died in Berkeley.