Andricus quercuscalifornicus (occasionally. A. californicus), or the California Gall Wasp, is a small wasp species that induces oak apple galls on white oaks, primarily the Valley Oak (Quercus lobata) but also other species such as Quercus berberidifolia. It is found from Washington, Oregon, and California to northern regions of Mexico. Often multiple wasps in different life stages occupy the same gall.