Joachim Rouault (died 1478), French soldier, was a member of an old family of Poitou. He attached himself to the Dauphin (afterwards Louis XI) and became his premier squire. He followed Louis in his expedition against the Swiss in 1444, distinguished himself in the war against England in 1448, and received the posts of governor of Blaye and Fronsac and constable of Bordeaux. After taking an important part in the Battle of Castillon (1453), which resulted in the defeat and death of John Talbot, 1st Earl of Shrewsbury, he fought against Jean V of Armagnac, in 1455, and in the following year made a fruitless expedition into Scotland.