Grammer is a vintage American acoustic guitar maker founded in Nashville in 1965 by country musician and Grand Ole Opry member Billy Grammer, music store operator Clyde Reid, and luthier J.W. Gower under the company name RG&G Musical Instruments, Inc. The original goal was a high-quality, affordable flat-top dreadnought built in Music City as an alternative to the increasingly expensive offerings from Gibson and Martin. Roughly 1,000 instruments were handcrafted at the original Poplar Avenue factory between 1965 and 1968.

The guitars are recognizable by their oversized pegheads, distinctive pickguards, and ornate bridges — early examples used a mustache-style bridge that was later replaced by a crown design — along with sunburst finishes in blue, yellow, and green. Specs included a 15½-inch lower bout, a 24½-inch scale, pearl inlays, and Grover tuners. After Ampeg acquired the company in 1968, the line was expanded to five models designated G, S, R, T, and B, and a factory fire prompted a move to a new Nashville facility before production wound down in the early 1970s.

During its short run the brand became closely associated with Nashville session and country players, with documented users including Red Sovine, Leon Rhodes, and Odell Martin, and Ampeg-era marketing featured endorsements from Porter Wagoner, Dolly Parton, Johnny Cash, and Merle Haggard. Surviving Grammer guitars, particularly the original RG&G-era dreadnoughts, are now sought after on the vintage market.

Grammer has 3 products cataloged on Equipboard, including Steel-string Acoustic Guitars. Their gear is featured by 3 artists, with the strongest followings in Rock, Folk, World, & Country, and Blues. Notable users include Ryan Adams, Joe Bonamassa, and Jenny Lewis.