Kazusa Hirotsune (上総 広常, died 1183) was a samurai lord and gōzoku in Kantō during the late Heian period.

[1] Hirotsune was a prominent gōzoku figure in the Kantō region during Minamoto no Yoritomo's call to arms.

In 1180, Hirotsune joined Minamoto no Yoritomo, who had lost the Battle of Ishibashiyama and planned a second attempt against the Taira clan in Awa Province.

[1] Hirotsune later came to conflict with Yoritomo who had established a samurai government but attached importance to the Imperial Court in Kyoto.

[1] Hirotsune and his eldest son Yoshitsune were assassinated by Kajiwara Kagetoki in 1183, upon the request of Yoritomo who had suspected him of conspiracy.