The black-billed nightingale-thrush (Catharus gracilirostris) is a small thrush endemic to the highlands of Costa Rica and western Panama.

The nest is a bulky lined cup constructed 1–5 m high in a scrub or small tree, and the typical clutch is 2 brown-blotched greenish-blue eggs.

The birds in the Chiriqui mountains of western Panama are slightly more rufous above and paler below than the Costa Rican population, and are sometimes considered as a subspecies, C. g. accentor.

The black-billed nightingale-thrush will normally forage low in vegetation or on the forest floor, alone on in pairs, progressing in hops and dashes with frequent stops.

It turns leaf litter in typical thrush fashion seeking insects and spiders, and also eats many small fruits.