Ren Jun 任峻 (d. 204), courtesy name Boda 伯達, was an official of the warlord Cao Cao 曹操 in the late decades of the Eastern Han period 東漢 (25-220 CE).
He hailed from Zhongmou 中牟 in the commandery of Henan 河南 (today in Henan province) and was an advisor to the local magistrate (ling 令) Yang Yuan 楊原, who took preparations for self-defense during the Yellow Turban rebellion 黃巾起義.
When Cao Cao pacified Zhongmou, Ren Jun and Zhang Bei 張備 decided to join this powerful man. Ren Jun was appointed commandant of cavalry (jiduwei 騎都尉) and was responsible for the supply management of Cao Cao's campaigning armies. As agricultural commandant (diannong zhonglangjiang 典農中郎將) he organized the founding of military agro-colonies (tuntian 屯田) in the territory under the control of Cao. Ren was responsible for the excellent logistical management during the battle of Guandu 官渡, and was rewarded with the title of Neighbourhood Marquis of Duting 都亭侯 and the post of commandant (xiaowei 校尉) of Changshui 長水. His posthumous title was Marquis Cheng 都亭成侯.