Ioannis S. "John" Coumantaros (1894–1981) was a Greek shipping and flour mills businessman.
He was the son of Stavros Coumantaros from Sparta, and had three older brothers, Theodoros, Nikolaos and Panayotis.
[1] The brothers founded the Evrotas flour mills in Piraeus, and moved into shipping in 1932.
[1] They had two children, a son, George S. Coumantaros, who married, Sophie Yannagas, the daughter of George Yannagas from Kasos, and they had two sons, Yannis and John, and three daughters, Flora, Elena and Eugenie.
[1] Their daughter Aikaterini "Dolly" I. Coumantaros married Nicholas P. "Nikos" Goulandris from Andros.