Cao Rui () (204 or 206 – 22 January 239), courtesy name Yuanzhong, was the second emperor of the state of Cao Wei during the Three Kingdoms period. His parentage is in dispute: his mother, Lady Zhen, was Yuan Xi's wife, but she later remarried Cao Pi, the first ruler of Wei. Based on conflicting accounts of his age, Pei Songzhi calculated that, in order to be Cao Pi's son, Cao Rui could not have been 33 (by East Asian age reckoning) when he died as recorded, so the recorded age was in error; Lu Bi and Mou Guangsheng argued instead that Cao Rui was Yuan Xi's son.