Emerald Guitars is a carbon fiber guitar maker based in Cavanacaw, St Johnston, County Donegal, Ireland. The company was founded in 1999 by Alistair Hay, whose background in Formula 1 powerboat racing gave him deep expertise in carbon fiber composites that he later applied to acoustic guitar building. After spending two years developing techniques and building over 30 prototypes, Hay began releasing instruments commercially, with the X20 dreadnought becoming the model that established the brand's reputation for ergonomic, non-traditional designs that played to the strengths of the material rather than imitating wood construction.

The company's catalog spans a range of all-carbon-fiber instruments including the X20 and X20-12 dreadnoughts, the X30 jumbo, the X7 parlour, the Balor 4- and 5-string basses, Weissenborn-style lap steels, and nylon-string models. Emerald also produces electric-acoustic hybrids such as the X10, the X10 Slimline, and the Virtuo, the latter equipped with Fishman Fluence pickups. The Black Opus series and a range of left-handed models round out the lineup, and the brand offers a 3D custom guitar configurator for buyers specifying finishes, inlays, and electronics.

Emerald has built a profile through high-profile commissions and endorsements, including Steve Vai's custom "Ultra Guitar" built in 2012, and "Bahamut," a guitar made in 2008 for Taiwanese-American pop star Wang Leehom. Other players associated with the brand include Irish singer Mickey Joe Harte, who performed with an Emerald at the 2003 Eurovision Song Contest, and Beverly McClellan. The company is regarded as one of the leading manufacturers in the niche carbon fiber acoustic guitar market.

Emerald Guitars has 7 products cataloged on Equipboard, including Acoustic-Electric Guitars, Solid Body Electric Guitars, and Mandolins. Their gear is featured by 4 artists, with the strongest followings in Rock and Blues. Notable users include Steve Vai, Joe Satriani, and Neil Citron.