Shrubs, evergreen, 1-4 m. Stems ± dimorphic, with elongate primary and short or somewhat elongate axillary shoots. Bark of 2d-year stems grayish or brownish purple, glabrous. Bud scales 2-3 mm, deciduous. Spines absent. Leaves 3-5(-7)-foliolate; petioles 0.2-0.7 cm. Leaflet blades thin but rigid; surfaces abaxially dull, papillose, adaxially dull, glaucous; terminal leaflet stalked in most or all leaves, blade 2.1-4.1 × 0.7-1.1 cm, 3-6 times as long as wide; lateral leaflet blades lance-ovate or lance-elliptic to lanceolate, 1-veined from base, base obtuse or rounded, margins plane or undulate, toothed, each with 4-11 teeth 0-1 mm high tipped with spines to 0.4-2 × 0.1-0.2 mm, apex acuminate. Inflorescences racemose, lax, 3-8-flowered, 2-5 cm; bracteoles membranous, apex acuminate, sometimes with proximal bracteoles leathery, spinose-acuminate. Flowers: anther filaments with distal pair of recurved lateral teeth. Berries yellowish red to red, not glaucous, spheric, 5-6 mm, juicy, solid.
Phenology: Flowering winter–spring (Feb–May).
Habitat: Sandy slopes and washes in chaparral, coastal scrub, and riparian scrub
Elevation: 0-600 m
Of conservation concern.
Berberis nevinii is known from scattered populations from San Francisquito Canyon, north of Valencia, south to Dripping Springs, near Aguanga. It is susceptible to infection by Puccinia graminis.