Saitō Toshimitsu (斎藤 利三) was a Japanese samurai of the Sengoku period and commander of Kuroi Castle. He was a retainer of Inaba Ittetsu, but later joined Akechi Mitsuhide. Oda Nobunaga was not pleased that Toshimitsu chose to work under Mitsuhide, and if not for Mitsuhide's intervention, Nobunaga would have killed him. Toshimitsu was also vital in Akechi's betrayal at Honnō-ji and at the Battle of Yamazaki. He was the father of the Lady Kasuga, who became a preeminent retainer of the Tokugawa shogunate.