Adagio is a musical instrument accessory brand operated by Advantage Music Ltd, a UK-based company that began selling Adagio-branded strings in the mid-2000s. The brand is designed in England and focuses on budget-to-mid-tier string sets and small accessories sold primarily through Amazon, eBay and the company's own site, with distribution reaching dozens of countries.

The catalog centers on guitar strings across all the common formats — Adagio Pro phosphor bronze and gold-coated acoustic sets, nickel-wound and anti-rust coated electric sets, nylon classical sets, 12-string acoustic sets, and roundwound and flatwound bass strings. The range extends to folk-instrument strings for violin, banjo and mandolin, along with accessories such as the Adagio Pro Bronze capo.

Rather than targeting the boutique or signature-artist market, Adagio positions itself as an affordable everyday-player brand, and much of its visibility comes from high-volume online marketplaces rather than dealer networks or artist endorsements.