Empress Cao (曹皇后, personal name unknown) (d. January 11, 937), formally Empress Hewuxian (和武憲皇后), was an empress of the Chinese Five Dynasties and Ten Kingdoms Period state Later Tang. Her husband was Later Tang's second emperor Li Siyuan (Emperor Mingzong), and she was empress dowager during the subsequent reigns of his son Li Conghou (Emperor Min) and adoptive son Li Congke. Eventually, when her son-in-law Shi Jingtang rebelled against Li Congke, establishing his own Later Jin and attacked the Later Tang capital Luoyang, she died in a mass suicide with Li Congke, his family, and some officers.
It is not known when the future Empress Cao was born — indeed, virtually nothing was known about her background even by the time of the next succeeding united Chinese dynasty, Song Dynasty, as the Song author of the New History of the Five Dynasties, Ouyang Xiu, indicated. It is further unclear how she became the wife — or one of multiple wives — of Li Siyuan's, or whether two other wives or concubines of his, Lady Xia (the mother of his sons Li Congrong and Li Conghou) and Lady Wei (the mother of his adoptive son Li Congke, who was fathered by Lady Wei's original husband, named Wang), were considered of coequal status with her or not. It appeared that she had no son, but had at least one daughter, the future Princess of Wei, then of Jin, who married Li Siyuan's subordinate officer Shi Jingtang. Sometime during the reign of Li Siyuan's adoptive brother and predecessor Li Cunxu, Lady Cao, as Li Siyuan's wife, was created the Lady of Chu. After Lady Xia's death, Li Siyuan also took a Lady Wang as a concubine, and Lady Wang became his favorite, as Lady Cao was described to favor the simple life.