| Emperor Xianzong of Dali | |
| Birth Date: | 1083 |
| Family Name: | Duan (段) |
| Given Name: | Yu (譽) or Heyu (和譽); later changed to Zhengyan (正嚴) Dharma name: Guanghong (廣弘) |
| Succession: | Emperor of Dali |
| Reign: | 1108–1147 |
| Predecessor: | Duan Zhengchun |
| Successor: | Duan Zhengxing |
| Reg-Type: | Grand Chancellors |
| Regent: | Gao Taiming (高泰明) (1108–1116) Gao Taiyun (高泰運) (1116–1119) Gao Mingshun (高明順) (1119–1129) Gao Shunzhen (高順貞) (1129–1141) Gao Liangcheng (高量成) (1141–1147) |
| Dynasty: | Dali |
| Era Dates: | Rixin (日新): 1108–1109 Wenzhi (文治): 1110–1121 Jiayong (嘉永): 1122–1128 Baotian (保天): 1129–1137 Guangyun (廣運): 1138–1147 |
| Temple Name: | Xianzong (憲宗) |
| Posthumous Name: | Emperor Xuanren (宣仁皇帝) |
| T: | 段譽 |
| S: | 段誉 |
| P: | Duàn Yù |
Duan Yu (1083–1176), courtesy name Heyu, also known by his temple name as the Emperor Xianzong of Dali, was the 16th[1] emperor of the Dali Kingdom, reigning 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 (段正嚴). He abdicated and became a monk in 1147 and was succeeded by his son Duan Zhengxing.
Duan Yu is fictionalized as one of the main characters in the wuxia Demi-Gods and Semi-Devils by Louis Cha.