Robert Marc Mazo, born in 1930 in Brooklyn, New York, is the son of Nathan and Rose Marion (Mazo) Mazo. While in high school in 1948, Mazo won the Seventh Science Talent Search with the project, "Reactions in Liquid Ammonia".
Mazo completed a A.B. at Harvard University in 1952, and an M.S. in Science at Yale University in 1953. With NSF fellowship funding, he earned a Doctor of Philosophy degree at Yale University in 1955, with his dissertation, Theoretical Studies On Low Temperature Phenomena, advised by Lars Onsager and John Gamble Kirkwood.
Mazo and Joan Ruth Spector wed in 1954, and their family includes a daughter and two sons.