Xu Shang (徐商), courtesy name Yisheng (義聲) or Qiuqing (秋卿), formally Viscount of Dongguan (東莞子), was an official of the Chinese dynasty Tang Dynasty, serving as a chancellor during the reign of Emperor Yizong of Tang.
It is not known when Xu Shang was born. He was a fifth-generation descendant of Xu Yougong (徐有功), a famed judge during the reign of Wu Zetian. His family claimed to be originally descended from mythical Xia Dynasty judge Gao Yao and traced its ancestry through a line of officials of Qin Dynasty, Han Dynasty, Cao Wei, Jin Dynasty (265-420), Liu Song, Southern Qi, Liang Dynasty, Chen Dynasty, and Tang Dynasty. His father Xu Zai (徐宰) served as a judge at the supreme court (大理寺, Dali Si). Xu Shang had at least one younger brother, Xu Gong (徐宮). By Xu Zai's time, the family was living in Xinzheng (新鄭, in modern Zhengzhou, Henan). In Xu Shang's youth, he was a hermit in the Zhongtiao Mountains (中條山), but he later came out of the hermit living and passed the imperial examinations in the Jinshi class.