Agnes of Aquitaine may refer to:
- Agnes of Poitou, (c. 1025 – December 14, 1077), wife of Henry III, Holy Roman Emperor
- Agnes of Aquitaine, Queen of León and Castile, (? d. c. 1078), wife of Alfonso VI of Castile
- Agnes of Aquitaine, Countess of Savoy, (d. c. 1097), wife of Peter I of Savoy
- Agnes of Aquitaine, Queen of Aragon and Navarre, (1072–1097), wife of King Peter I of Aragon and Navarre
- Agnes of Aquitaine, Queen of Aragon, (d. c. 1160) wife of Aimery V of Thours and Ramiro II of Aragon
- Agnes, wife of Ramiro I of Aragon, (fl. 1054–1062), perhaps of Aquitaine, perhaps identical to the Countess of Savoy