Aymer de Valence, 2nd Earl of Pembroke (c. 1270 – 23 June 1324), was an Anglo-French nobleman. Though primarily active in England, he also had strong connections with the French royal house. One of the wealthiest and most powerful men of his age, he was a central player in the conflicts between Edward II of England and his nobility, particularly Thomas, 2nd Earl of Lancaster. Pembroke was one of the Lords Ordainers appointed to restrict the power of Edward II and his favourite Piers Gaveston. His position changed with the great insult he suffered when Gaveston, as a prisoner in his custody whom he had sworn to protect, was removed and beheaded at the instigation of Lancaster. This led Pembroke into close and lifelong cooperation with the king. Later in life, however, political circumstances combined with financial difficulties would cause him problems, driving him away from the centre of power.

Aymer de Valence was the son of William de Valence, 1st Earl of Pembroke, the half-brother of King Henry III of England. He inherited his father's French lands on his death in 1296, and he later succeeded to the Earldom on his mother's death in 1307. Aymer was knighted in 1297 while serving under King Edward I of England during his campaign in Flanders, and, in 1304, King Edward appointed him to head a council which would govern Scotland for the English crown; after Robert Bruce murdered John Comyn in 1306, Aymer mobilized the Perth garrison and met Robert in battle at Methven, where he destroyed the Scottish army and forced Robert into hiding. In 1307, Edward I died and was succeeded by his incapable son Edward II of England, and Aymer - now the Earl of Pembroke - helped to exile the King's favorite Piers Gaveston in 1311. In 1312, however, Pembroke sided with the King after the rebellious barons executed Gaveston without the King's permission. In 1314, he was appointed the King's lieutenant in Scotland, and he helped to lead Edward away from the battlefield following the disastrous Battle of Bannockburn. From 1316 to 1318, he helped to quell a conspiracy against King Edward, and, following the 1322 Battle of Boroughbridge, Pembroke voted to have Thomas, 2nd Earl of Lancaster executed for treason. In 1324, Pembroke died in Picardy while serving as an envoy to France. He was buried at Westminster Abbey.