Ren Ao 任敖 (d. 178 BCE) was a high official of the early Former Han period 前漢 (206 BCE-8 CE).
He hailed from Pei 沛 (modern Peixian 沛縣, Jiangsu), where he was a jail overseer under the Qin dynasty 秦 (221-206 BCE). Ren Ao was a friend of Liu Bang 劉邦, the eventual founder of the Han dynasty (as Emperor Gaozu 漢高祖, (r. 206-195 BCE). When Liu Bang rose weapons against the Qin dynasty, Ren Ao was made a scribe (yushi 御史) and took over control of the region of Feng 豐 near the former capital of the Qin.
When Liu Bang was made King of Han by the hegemonial lord Xiang Yu 項羽, Ren Ao was appointed governor (taishou 太守) of Shangdang 上黨, a city which he defended against the rebel Chen Xi 陳豨. He was therefore in 196 given the title of Marquis of Guang'a 廣阿侯.