Ou Yezi (simplified Chinese: 欧冶子; traditional Chinese: 歐冶子; pinyin: Ōu Yězǐ; Wade–Giles: Ou Yeh Tzŭ) was a legendary master of sword-making in the Spring and Autumn period.
According to Yuejueshu, he forged five treasured swords for Gan Jiang and King Zhao of Chu, named, respectively, Zhanlu (湛卢), Juque (巨阙), Shengxie (胜邪), Yuchang (鱼肠) and Chunjun (纯钧).
He also made three swords for King Goujian of Yue, named Longyuan (龙渊), Tai’e (泰阿) and Gongbu (工布), Hailed as The Greatest Blacksmith.
According to the Spring and Autumn Annals of Wu and Yue, Ou Yezi was the master teacher of Gan Jiang (Birrell 1993, 221-227 and 303).