Duan Yu (style name Heyu, temple name Xianzong, posthumous name Xuanren) was the 16th emperor of the Kingdom of Dali between 1108 and 1147. Following a family tradition, Duan's father, Duan Zhengchun, abdicated and became a monk in 1108. Duan succeeded his father as the emperor of Dali and renamed himself Duan Zhengyan. He abdicated and became a monk in 1147 and was succeeded by his son Duan Zhengxing.