Kokia kauaiensis is a tree that grows 5–10 meters high. It has simple, alternate leaves with orbicular blades measuring 12–25 cm wide. These blades can be 7-lobed- or 11-lobed with shallow, angulate, or deltate divisions. The base of the leaves is cordate, typically with a closed sinus. While the upper surfaces are glabrate, the lower surfaces are densely pubescent near the base and at the apex of the petioles. The margins are entire or nearly so. The petioles are usually as long as or longer than the blades, are deciduous, and leave prominent scars. The stipules are caducous. The flowers are solitary and cluster near the ends of branches, axillary with pedicels ranging from 3–9 cm long, articulate near the middle, and with a persistent bract. The plant lacks terminal nectaries. The involucral bracts are three, broadly ovate, ranging from 40–60 mm long, glabrous, distinct or connate at the base, entire or lobed, and sparsely pilose toward the base with an obtuse–sinuate apex. These become accrescent and leathery in fruit. The flowers are bisexual (perfect), with a calyx of connate sepals forming a cylindrical structure, irregularly 2–5 lobed, the lobes caducous, valvate in bud. The corolla is zygomorphic (bilaterally symmetric), consisting of 5 brick-red petals, 10–15 cm long, obovate, curved in the bud, densely yellowish silky pubescent, reflexed above at anthesis, and twisted at the base. The stamens form a monadelphous staminal column, exserted, curved, and antheriferous in the upper third to half, terminated by five teeth. The ovary is superior, 5-celled, with ovules one per cell, placentation axile, and a clavate style exceeding the staminal column, unbranched and stigmatically lobed at the apex. The fruits are loculicidal dehiscent capsules, ovoid, up to 3.7 cm long, apex acuminate, and woody. The seeds are obovoid, 20 mm long, pubescent with hairs up to 10 mm long, and may contain an endosperm. It is found in diverse mesic forests between 350-660 meters.