Grammatico Amps is a boutique guitar amplifier company founded by builder John Grammatico, originally based in Texas and later operating out of Nashville. The company hand-wires vacuum-tube amplifiers aimed at capturing the recorded tones of classic Fender, Marshall, Dumble, and Trainwreck circuits using modern, tighter-tolerance components.

The lineup includes the Kingsville, a 5F6-A Bassman-inspired head developed with Jimmie Vaughan, who has performed with it live since 2009. Other models include the LaGrange, a 5E3 Tweed Deluxe replica; the ATX, a Vibroverb-style amp named for Austin's airport code; the PDR, a 6V6 combo with spring reverb and tube tremolo voiced toward Dumble Steel String Singer territory; the GSG100, inspired by the Dumble Overdrive Special; and the Blackpool, which targets early Marshall tones.

Grammatico amps have been used by players including Jimmie Vaughan, Mike Keller of the Fabulous Thunderbirds, Daniel Donato, JB Eckl, and Bob Weir, who tracked with a PDR at RCA Studio A. The brand sits in the vintage-faithful, low-volume boutique segment of the tube amp market, with builds typically sold direct and through Reverb.

Grammatico has 2 products cataloged on Equipboard, including Combo Guitar Amplifiers. Their gear is featured by 5 artists, with the strongest followings in Rock, Blues, and Funk / Soul. Notable users include Dave Grohl, Buddy Guy, and Doyle Bramhall II.