Cao Zhen, courtesy name Zidan, was a military general of the state of Cao Wei during the Three Kingdoms period of China. He was an adopted son of Cao Cao, a warlord who rose to power in the late Eastern Han dynasty and laid the foundation for Wei. After Cao Cao's death and the end of the Eastern Han dynasty, Cao Zhen served under Cao Pi and Cao Rui, the first two emperors of Wei. He is best known for leading a successful defence of Wei from the first two of a series of invasions by Wei's rival state, Shu Han, between 228 and 229.

Wei (220–266), known as Cao Wei (曹魏) or Former Wei in historiography, was a dynastic state of China and one of the three major states that competed for supremacy over China in the Three Kingdoms period. With its capital initially located at Xuchang, and thereafter Luoyang, the state was established by Cao Pi in 220, based upon the foundations laid by his father, Cao Cao, towards the end of the Eastern Han dynasty.