Masaki Doi (土井 真樹, Doi Masaki?, born July 7, 1960) is a Japanese politician serving in the House of Representatives in the Diet (national legislature) as a member of the Liberal Democratic Party. A native of Kariya, Aichi and graduate of the University of Tokyo he was elected for the first time in 2005. He also passed the examination for Certified Public Accountant in 1983.