Smilax jamesii is a species of flowering plant in the greenbriar family known by the common name English Peak greenbriar. It is to northern California, where it is known from the Klamath Mountains and the southernmost peaks of the Cascade Range. It has also been reported from nearby locations in southwestern Oregon. It grows in moist areas such as lakesides and streambanks in mountain coniferous forest habitat. It was discovered to be a new species when herbarium specimens thought to be Smilax californica were reexamined.