| Saitō Toshimitsu | |
| Native Name: | 斎藤 利三 |
| Birth Date: | 1534 |
| Birth Place: | Mino Province |
| Order: | Lord of Kuroi Castle |
| Term Start: | 1579 |
| Term End: | 1582 |
| Predecessor: | Akai Naomasa |
| Successor: | Horio Yoshiharu |
| Children: | Lady Kasuga |
| Allegiance: | Saitō clan Inaba clan Akechi clan |
| Battles: | Tanba Campaign (1575) Siege of Kuroi Castle (1579) Honnoji Incident (1582) Battle of Yamazaki (1582) |
| Commands: | Kuroi Castle |
was a Japanese samurai of the Sengoku period. He was a castle commander of Kuroi Castle.[1] He was a retainer of Inaba Ittetsu,[2] 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 for the Akechi action at Honnō-ji and the Battle of Yamazaki.[3]
He was the father of the Lady Kasuga, who became a preeminent retainer of the Tokugawa Shogunate.