Wang Ji'en (died 999), previously Zhang Dejun, was an eunuch and a military general during imperial China's Later Zhou and the following Song dynasty.
Wang Ji'en was born in Shanzhou (modern Shan County, Henan). His original surname was Wang, but his adoptive father Gentleman Zhang named him Zhang Dejun. He was one of the higher-ranked eunuch during the reign of Chai Rong, the second emperor of the Later Zhou.
As he requested to change his surname back to his ancestral surname, Emperor Taizu of Song named him Wang Ji'en.