Riverhead is a Japanese electric guitar and bass brand founded in 1984 by Satoshi "Kei" Yatsuzuka, the luthier behind Headway and Deviser. Production began in Matsumoto City, Japan, the country's longstanding hub of guitar manufacturing, where Headway had been building high-end acoustics since the late 1970s before transitioning to electric solidbodies. Riverhead served as Headway's forward-looking, design-driven line and quickly built a reputation for unconventional shapes and headless construction inspired by the early-1980s Steinberger movement.

The brand's catalog spans several distinctive series, including the Unicorn (RUB basses and RUG guitars), the angular, faceted Phantom (RPB/RPG), and the Wizard, Jerk, Jupiter, and RS lines. Riverhead instruments are particularly associated with their headless basses — flying-V and Steinberger-influenced designs that found a following among players seeking compact, ergonomic bodies and a modern aesthetic. Production was paused in the mid-1980s and later revived for the Japanese domestic market in 1992. Manufacturing has since shifted to a facility in the Philippines under Yatsuzuka's direction.

Riverhead shares its lineage with sister brands produced by the same Headway/Deviser organization, including Bacchus, Momose, and STR, and is generally regarded by collectors and enthusiasts on forums such as TalkBass and the Tokai Forum as offering build quality on par with higher-end Japanese makers of the era. Vintage 1980s Riverhead pieces remain sought-after on the used market.

Riverhead has 3 products cataloged on Equipboard, including Electric Basses. Their gear is featured by 1 artist, with the strongest followings in Rock. Notable users include Stephanie Ashworth.