|Posthumous name||Prince Huai (traditional Chinese: 懷王; simplified Chinese: 怀王; pinyin: Huái Wáng; Wade–Giles: Huai Wang)|
Cao Xiong (birth and death dates unknown) was a son of Cao Cao, a warlord who rose to power towards the end of the Han Dynasty and laid the foundation of the state of Cao Wei in the Three Kingdoms period. Not much was recorded in history about Cao Xiong, except that he died at a relatively young age. His mother was Lady Bian, who also bore Cao Cao another three sons — Cao Pi, Cao Zhang and Cao Zhi. Cao Xiong was the youngest of the four.
In 221, after Cao Pi ended the Han Dynasty and established Wei, he granted Cao Xiong the posthumous title of "Duke Huai of Xiao" (蕭懷公). In 229, during the reign of Cao Pi's son Cao Rui, Cao Xiong was posthumously elevated to the status of a prince, so his posthumous title became "Prince Huai of Xiao" (蕭懷王).
In 234, Cao Xiong's son, Cao Bing (曹炳), was granted a princedom with 2,500 taxable households. The princedom was named "Xiao" (蕭), per Cao Xiong's posthumous title. Cao Bing died six years later and his princedom was abolished because he had no heir. He was given the posthumous name "Prince Ai" (哀王).
Cao Xiong was briefly mentioned in Luo Guanzhong's historical novel Romance of the Three Kingdoms. In 220, when Cao Cao died, Cao Xiong refused to go to Luoyang to attend his father's funeral. Acting on Hua Xin's suggestion, Cao Pi sent a messenger to reprimand his brother, but the messenger returned later and reported that Cao Xiong had hanged himself for fear of receiving punishment. Cao Pi had his brother buried with full honours and gave him the posthumous title "Prince Huai of Xiao".
- (蕭懷王熊，早薨。) Sanguozhi vol. 19.
- (武皇帝二十五男：卞皇后生文皇帝、任城威王彰、陳思王植、蕭懷王熊， ...) Sanguozhi vol. 20.
- (黃初二年追封謚蕭懷公。太和三年，又追封爵為王。) Sanguozhi vol. 19.
- (青龍二年，子哀王炳嗣，食邑二千五百戶。六年薨，無子，國除。) Sanguozhi vol. 19.
- (卻說華歆奏曹丕曰：「鄢陵侯已交割軍馬，赴本國去了；臨淄侯植，蕭懷侯熊，二人竟不來奔喪，理當問罪。」丕從之，即分遣二使往二處問罪。不一日，蕭懷使者回報：「蕭懷侯曹熊懼罪，自縊身死。」丕令厚葬之，追贈蕭懷王。) Sanguo Yanyi ch. 79.
- Chen Shou. Records of the Three Kingdoms (Sanguozhi).
- Luo Guanzhong. Romance of the Three Kingdoms (Sanguo Yanyi).