Zhu Jiuyuan (1473 – 1524) was a Master Assassin and Mentor of the Chinese Brotherood of Assassins. He notably trained Shao Jun from initiate to the full rank of Assassin during the secret war in Beijing, after Wang Yangming's disappearance to escape the Great Rites Controversy.

After the Jiajing Emperor, under the influence of the Eight Tigers, initiated a purge of the Assassins, Jiuyuan fled with Jun to Europe in an attempt to find Ezio Auditore da Firenze, the retired Mentor of the Italian Assassins, and gain his help to rebuild the Chinese Brotherhood. However, Jiuyuan was killed in Venice by Templar agents before they reached his villa.