Nigrelli Guitars is an Argentine luthier shop founded by Sergio Nigrelli, who began building instruments as a teenager under the guidance of his father and completed his first commissioned electric bass in 1987. Operating out of a workshop in Ituzaingó, in the western suburbs of Buenos Aires, Nigrelli has run his own production of guitars and basses since the 1990s, with a stated focus on offering high-quality custom instruments at accessible price points.

The shop builds electric guitars and basses across archtop, hollow-body, and solid-body designs, as well as acoustic instruments, alongside repair work and lutherie instruction. One of the better-known designs from the workshop is the Alchimia RCM, a signature model developed for Argentine rock guitarist Richard Coleman. Other Argentine rock musicians associated with Nigrelli instruments include Zeta Bosio of Soda Stereo, and players from Los Piojos and Los Caballeros de la Quema.

Beyond his own brand, Sergio Nigrelli has served as president of the Asociación Argentina de Luthiers and runs a lutherie school in Ituzaingó, making him a notable figure in the broader Argentine instrument-building scene.

Nigrelli has 2 products cataloged on Equipboard. Their gear is featured by 2 artists, with the strongest followings in Rock, Pop, and Funk / Soul. Notable users include Richard Coleman and Ariel Pozzo.