Sima You (Chinese: 司馬攸; pinyin: Sīmǎ Yōu; 246[2] – 27 April 283[3]), courtesy name Dayou (大猷), posthumously known as Prince Xian of Qi (齐献王), was an imperial prince of the Western Jin dynasty of China.
It is known that Sima You was a person of mild-mannered character, who was expected to become King of Jin, but ended up being passed over due to his young age.
[4] When Emperor Wu appointed his developmentally disabled son heir apparent, he was concerned that his subjects viewed Sima You too favourably.
[6] Despite this, Emperor Wu continued to bestow titles upon Sima You, including the post of sikong on 16 September 276, replacing Jia Chong (who was made Grand Commandant).
[9] With his father-in-law Jia Chong having died a few months earlier in May 282, Sima You had one fewer powerful voice to intercede on his behalf.