Tõnu Naissoo (born March 18, 1951) is an Estonian composer and jazz pianist.
Tõnu Naissoo was born in Tallinn. He is the son of composer Uno Naissoo. He began studying classical piano at the age of six at the Tallinn Music School, graduating in 1970 with a degree in music theory. In 1982 he graduated from the Tallinn State Conservatory in composition under instruction from Eino Tamberg.
He has played on several musical groups, including Tõnu Naissoo Trio, Optimistid (1967–1968), Collage (1967–1972), Sinilind (1971–1972), Laine (1972–1976), Synthesis (1977–1980), Kaseke (1980–1981). For about 30 years he has been a pianist in the Viru Hotel.