Comarostaphylis diversifolia, known by the common names summer holly and California comarostaphylos, is a species of shrub in the heath family.

Comarostaphylis diversifolia is an erect shrub which can exceed 4 metres (13 ft) in height.

Its bark is gray and shreddy and the tough, evergreen leaves are oval in shape and sometimes toothed.

The inflorescence is a raceme of urn-shaped flowers very similar to those of the related shrubs, the manzanitas.

The fruit is a bright red, juicy drupe with a bumpy skin.