Raymond of Poitiers (c. 1115 – 29 June 1149) was Prince of Antioch from 1136 to 1149. He was the younger son of William IX, Duke of Aquitaine and his wife Philippa, Countess of Toulouse, born in the very year that his father the Duke began his infamous liaison with Dangereuse de Chatelherault.
Following the death of Prince Bohemund II of Antioch in 1130, the principality came under the regency first of King Baldwin II (1130–31), then King Fulk (1131–35), and finally Princess Alice (1135–36), Bohemond's widow. The reigning princess was Bohemond II's daughter, Constance (born 1127). Against the wishes of Alice, a marriage was arranged for Constance with Raymond, at the time staying in England, which he left only after the death of Henry I on 1 December 1135.
Upon hearing word that Raymond was going to pass through his lands in order to marry the princess of Antioch, King Roger II of Sicily ordered him arrested. By a series of subterfuges, Raymond passed through southern Italy and only arrived at Antioch after 19 April 1136. Patriarch Ralph of Domfront then convinced Alice that Raymond was there to marry her, whereupon she allowed him to enter Antioch (whose loyal garrison had refused him entry) and the patriarch married him to Constance. Alice then left the city, now under the control of Raymond and Ralph.
The first years of their joint rule were spent in conflicts with the Byzantine Emperor John II Comnenus, who had come south partly to recover Cilicia from Leo of Armenia, and to reassert his rights over Antioch. Raymond was forced to pay homage, and even to promise to cede his principality as soon as he was recompensed by a new fief, which John promised to carve out for him in the Muslim territory to the east of Antioch. The expedition of 1138, in which Raymond joined with John, and which was to conquer this territory, proved a failure. The expedition culminated in the unsuccessful Siege of Shaizar. Raymond was not anxious to help the emperor to acquire new territories, when their acquisition only meant for him the loss of Antioch. John Comnenus returned unsuccessful to Constantinople, after demanding from Raymond, without response, the surrender of the citadel of Antioch.