The Coast live oak, Quercus agrifolia, also called the California live oak, is an evergeen oak, highly variable and often shrubby, found in the coastal regions of southwestern North America from Mendocino County, California south to northern Baja California in Mexico. The dark-green leaves are usually small, thick and spiny-toothed.

The Coast live oak is classified in the red oak section (Quercus sect. Lobatae). Several hybrids between Coast live oak and other red oak species have been documented. Hybrids with Interior live oak (Q. wislizenii) are known in many areas in northern California. Coast live oak also hybridizes with Nuttall's scrub oak (Q. dumosa) and Shreve oak (Q. parvula var. shrevii). All these oak species show evidence of introgression with one another.

The name Quercus agrifolia literally means "field-leaved oak", and is generally thought to be an error by the describing botanist for "aquifolia", "holly-leaved".