The straight-billed woodcreeper (Dendroplex picus) is a species of bird in the subfamily Dendrocolaptinae of the ovenbird family Furnariidae. It is found in Panama, Trinidad, and in every mainland South American country except Chile, Argentina, Paraguay and Uruguay.
The straight-billed woodcreeper was formally described in 1788 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the orioles in the genus Oriolus and coined the binomial name Oriolus picus. The specific epithet picus is the Latin word for a woodpecker. Gmelin based his description on "Le pic-grimpereaux" from Cayenne that had been described and illustrated in 1780 by the French polymath, the Comte de Buffon. The straight-billed woodcreeper was later moved to genus Dendroplex that was introduced in 1827 by William Swainson. In the 1950s genus Dendroplex was merged into genus Xyphorhynchus but in the early 2000s it was resurrected for this species and Zimmer's woodcreeper (D. kienerii).
Thirteen subspecies of the straight-billed woodcreeper are recognized.