Don Grosh Custom Guitars is a small-batch electric guitar and bass builder based in Broomfield, Colorado, just north of Denver. Founder Don Grosh started in his father's shop before joining Valley Arts in North Hollywood in 1985, where he eventually ran the floor as shop foreman building instruments for high-profile session players. He launched his own company in 1993 out of a garage in Santa Clarita, California, expanded into a dedicated shop in 2001, and relocated the operation to the Colorado foothills in 2005.

The company is known for bolt-on and set-neck instruments rooted in classic American shapes, executed with a more refined, modern feel. Core models include the Retro Classic and NOS Retro (vintage-leaning T-style and S-style designs), the ElectraJet, SuperJet, and TurboJet offset-inspired guitars, the DeltaJet SC single-cut, and a line of basses including the T4, P4, J4, and J5. Grosh also winds its own pickups in-house, including S-Type and T-Type single-coils, the G-90, the Blown '59, and the Small Block 302 and 327 humbuckers, which are offered both in their guitars and as standalone replacement parts.

Every instrument is built to order rather than from a stock catalog, and the shop's reputation in the boutique guitar community rests on tight tolerances, light weight, and a feel aimed at working players rather than collectors.

Don Grosh has 4 products cataloged on Equipboard, including Solid Body Electric Guitars and Electric Guitar Pickups. Their gear is featured by 3 artists, with the strongest followings in Rock, Pop, and Funk / Soul. Notable users include Mark Lettieri, George Pajon, Jr., and Ian Crawford.