RainSong is an innovative acoustic guitar manufacturer currently based in Woodinville, Washington. The company makes high-end carbon fibre bodied acoustics and acoustic electrics. Their model include nylon string guitars, 12-string guitars, and a jazz archtop. Later models have a bi-directional weave and slightly better cosmetic appearance, due to changes in their carbon fibre production technique (which RainSong call Projection Tuned Layering). The production technique and materials mean that the outer skin of the guitar is very strong, and traditional internal bracing seen on wooden acoustics is largely unneccesary.

The company was formed in the 1990s in Kihei, Maui, Hawaii by aerospace engineer and guitarist Dr. John Decker. Early models were designed by luthier Lorenzo Pimentel. The company moved production to Washington from Hawaii in 2001. After the move to Washington, the company also introduced a lower end line of budget models with a carbon fibre top and mahogany sides and back. These use tops made in Woodinville but the guitars are assembled in Korea and sell for around half the price of the full carbon fibre models.