- Birth: 1524?
- Death: 1573
- Distinction: Ômi warlord
- Title: Shimotsuke no kami
- Sons: Asai Nagamasa and Asai Masamoto
Hisamasa was a son of Asai Sukemasa and succeeded his father as lord of Odani castle. According to the Asai Sandai-ki, Hisamasa was a less then capable leader or at least inferior to his father. He lost land to the Rokkaku and made peace with them in 1558, a move that proved both unpopular with the Asai retainers and short-lived. He shared command of the Asai army at the Battle of Norada (1560) with his son, Nagamasa. Nagamasa's brilliant preformance in that victory over the Rokkaku convinced the Asai retainers that he was the better man to lead the family and Hisamasa was compelled to step aside. Hisamasa continued to live in Odani castle and committed suicide when the Asai fell to the Oda in 1573. Despite his lackluster reputation, Hisamasa does seem to have been a competent enough administrator and, among other endeavors, mediated a dispute over irrigation in his fief and strengthened the foundations of the Asai house in northern Ômi. He had sent a daughter to marry Saitô Yoshitatsu of Mino and this girl became the mother of Saitô Tatsuoki, the lord of that province from 1561 to 1567.