Mark Sandman (September 24, 1952 – July 3, 1999) was an American singer, songwriter, musical instrument inventor, multi-instrumentalist and comic writer. He was an indie rock icon and longtime fixture in the Boston/Cambridge music scene, best known as the lead singer and slide bass player of the band Morphine. Sandman was also a member of the blues-rock band Treat Her Right and founder of Hi-n-Dry, a recording studio and independent record label.

Sandman was known for his deep distinctive Baritone voice and was notorious for his temper with the media on speculation of his private life as well as his dark, charismatic, and mysterious demeanor, which made him an unpredictable character in person.