Motoyasu Mori (???) was a Mori and Western Army general from Chugoku. He was most famous for leading the Siege of Otsu Castle, alongside Yoshihiro Shimazu and Muneshige Tachibana.


Motoyasu Mori was a relative of Terumoto Mori and Takakage Kobayakawa, and was a member of the Mori clan. In 1598, after the death of Hideyoshi Toyotomi, Motoyasu and clansman Hidemoto Mori joined the Western Army, Toyotomi loyalists, rather than fight for the Tokugawa clan-loyal Eastern Army, who were stronger. In 1600, he led the siege of former Western Army general Takatsugu Kyogoku's stronghold of Otsu Castle, and took it, despite being wounded and suffering heavy losses. The rest of his life is unknown.