The Long-billed Thrasher is a medium-sized resident songbird of South Texas and eastern Mexico.

It is slender and long-tailed, averaging 26.5"?29 cm (10.5"?11.5 in) in length and about 70 g (2.5 oz) in weight. Adults are brown above with a brighter rufous tinge on the rump and tail, off-white below with a black streak on each side of the throat (the malar) and heavy black streaks on the breast and belly, especially the sides of the breast. There are two pale wingbars. The head is grayish, especially the face. The bill is black, fairly long, and slightly down-curved, and the eyes are orange to orange-yellow. Immatures resemble adults but have less distinct markings and buffier wingbars.

The song is warbling and resembles other thrashers' songs but is especially rich and musical, though occasionally scratchy. Phrases are often repeated two to four times. A distinctive call is a "loud, rich whistle cleeooeep" or "mellow, whistled tweeooip or ooeh"; other calls include "a loud sharp chak" and "a very rapid, sharp rattle chtttr" resembling calls of its close relative the Brown Thrasher.

This species is resident from South Texas through Tamaulipas and eastern Coahuila along the Atlantic slope of Mexico to central Veracruz. It occurs in brushy or thicketed habitats of all kinds.

It usually stays hidden on or near the ground, though it may sing from conspicuous perches. Its food is mostly insects and fruit; it searches for insects on the ground by energetically turning over ("thrashing") leaves and other litter.

The nest is a bulky cup placed in thick low or mid-height vegetation and made of materials such as twigs and grasses. The female lays 2 to 5 eggs described as bluish-white with dense reddish-brown and gray speckles or greenish-white with tiny, dense, "dingy brown" speckles.

There are two subspecies: T. l. longirostre, brighter rufous above, from southeastern San Luis Potosí and northern Veracruz south, and T. l. senetti, grayer above, from northern Veracruz north.