JEG is a boutique guitar and bass workshop founded in Buenos Aires, Argentina, by luthier Javier Ezequiel Gandolfo. Gandolfo trained in cabinetmaking at the Don Orione arts and crafts school in Tigre before beginning formal luthiery studies in 1998 under Hernán Rojo and Ricardo Miranda. He launched JEG in 2000 and has built hundreds of instruments since.

The shop focuses exclusively on custom-built electric guitars and electric basses, designed and shaped to each client's specifications. Builds are documented on the JEG YouTube channel and Flickr, where Gandolfo posts step-by-step photos of body shaping, sanding, neck carving, and finishing on commissioned instruments.

JEG operates as a single-luthier boutique brand rather than a production builder, and its presence is largely concentrated in the Argentine and broader Latin American guitar community.

JEG has 3 products cataloged on Equipboard, including Solid Body Electric Guitars. Their gear is featured by 2 artists, with the strongest followings in Rock and Jazz. Notable users include Hernán Rupolo and Marilina Bertoldi.