John de Warenne, 7th Earl of Surrey

John de Warenne, 7th Earl of Surrey (1286–1347), was the last Warenne earl of Surrey. A minor when his grandfather died in 1304, he became a royal ward and in 1306 received his lands and married Edward I’s granddaughter Joan of Bar. The marriage was childless and his attempts at divorce failed.

In 1312 he helped capture Edward II’s favourite Piers Gaveston. A private war with Thomas, Earl of Lancaster, cost him much of his estates; after sitting in judgment on Lancaster in 1322, he recovered his Yorkshire lands in 1326. One of the last earls loyal to Edward II, he went over to Queen Isabella after Arundel's execution and urged the king's abdication in 1327.

As guardian of Edward Balliol he joined his Scottish campaign and was named earl of Strathearn. He died at Conisbrough Castle in 1347, the earldom passing to his nephew Richard FitzAlan.