Empress Xu (許皇后) (personal name unknown) (died 8 BC) was an empress during Han Dynasty, who came from a powerful family and who was initially very much loved by her husband Emperor Cheng, but who eventually lost favor and, as a result of the machinations of her eventual successor, Empress Zhao Feiyan, was deposed. After she was removed, she tried in vain to regain a measure of dignity by conspiring with her husband's cousin Chunyu Zhang (淳于長), but that conspiracy would eventually lead to her being forced to commit suicide.
Empress Xu was the daughter of Xu Jia (許嘉), the Marquess of Ping'en and the brother of Emperor Xuan's first wife Empress Xu Pingjun, who was the mother of Emperor Yuan. Emperor Yuan frequently grieved for his mother because she was murdered while still young by Huo Guang's wife Xian (顯), so he resolved to marry a daughter of the Xu clan to his son, Crown Prince Ao (劉驁), and he eventually decided on his cousin. When the young couple got married, then-Crown Prince Ao loved his wife dearly. However, they had no children; then-Consort Xu miscarried a male child while her husband was crown prince, and would miscarry a female child when she later became empress, but she would have no births. She was described to have been, unlike even most noble women of the time, well-learned in literature and formal writing.
In 33 BC, then-Consort Xu's father-in-law Emperor Yuan died, and her husband Crown Prince Ao succeeded to the throne as Emperor Cheng. In 31 BC, he created her empress. He favored her greatly, but also had another favorite, Consort Ban, who also was childless. Because both the empress and Consort Ban lacked children, Emperor Cheng's mother Empress Dowager Wang Zhengjun became concerned, and she encouraged him to take on more and more concubines in the hopes of producing an imperial heir, but none would come.