Joe Monzo (b. 1962) is an American microtonal composer, tuning theorist, and author. He tutors people in computing and music composition. Born and raised in Philadelphia, since 2000 he has been living in San Diego, California. He often goes by the nickname "monz", and is affiliated with the Sonic Arts center for microtonal music.
Monzo is known for his book JustMusic: A New Harmony, and numerous web pages such as A Century of New Music in Vienna. In 2002, he became co-founder of Tonalsoft, which produces the microtonal music composition program Tonescape. Monzo also assembled the massive Tonalsoft Encyclopedia of Microtonal Music Theory.