Plants epiphytic, cespitose, to 20 cm. Stems without pseudobulbs, or apparently so. Leaves 4-5 per shoot; blade linear-elliptic, 7-27 × 1.3-3 cm, leathery, apex unequally 2-lobed. Inflorescences several per leaf axil, successively borne and barely emerging, apparently supported on short, lateral rhizomes. Flowers yellow; sepals elliptic to ovate, 13-15 × 4-6 mm, apex acute, thickened; petals oblanceolate, 11-14 × 3-4 mm, apex acute; lip articulate with column foot, rhombic, 12-15 × 5-6 mm, lateral lobes inflexed toward column, constricted distal to middle; callus sticky, linear; column arching, cylindric, 9-10 mm, foot 1-2 mm. Capsules 2.5-3 cm.

Flowering throughout year (fall--winter, Fla.). Epiphytic; 0--10[--1300] m; Fla.; Mexico; West Indies; Central America; South America.

Maxillaria crassifolia is self-pollinating in Florida. It occurs much more commonly in the rest of its range.