Moon Guitars is a Japanese custom guitar and bass maker based in Machida, Tokyo, launched in 1978 with production beginning at parent workshop PGM in 1979. The company built its reputation as a "custom component" builder, pairing carefully selected neck and body woods with high-grade domestic and imported hardware to meet the demands of working professionals. Its catalog centers on bolt-neck guitars like the ST, TE, JM-C, and JG, and basses including the JB, PB, PJ, and JJ series, along with the Reggae Master (RM) model.

The brand became widely known in the 1980s after Steve Lukather of Toto played an early Moon ST, and the company has since been associated with Japanese session and jazz-fusion players such as Mitsuru Sutoh of T-Square, guitarist Shun Kikuta, Toshiki Kadomatsu, and Kyoji Yamamoto, as well as funk bassist Larry Graham. Moon offers both order-made instruments and standard-spec production runs, and the shop also produces artist signature models developed with its endorsers.

Moon Guitars Japan has 11 products cataloged on Equipboard, including Electric Basses and Solid Body Electric Guitars. Their gear is featured by 7 artists, with the strongest followings in Rock, Pop, and Funk / Soul. Notable users include Toshiki Kadomatsu, Prince, and Steve Lukather.