Masamitsu Naito

 is a Japanese politician of the Democratic Party of Japan, a member of the House of Councillors in the Diet (national legislature). A native of Okazaki, Aichi, he graduated from the University of Tokyo and received master's degrees from it and Columbia University, he was elected to the House of Councillors for the first time in 1998 after running unsuccessfully for the prefectural assembly of Tokyo.
In November 2017 an investigation conducted by the International Consortium of Investigative Journalism cited his name in the list of politicians named in "Paradise Papers" allegations.