Bartholomew Badlesmere, Baron (1275-1322), English nobleman, was the son and heir of Gunselm de Badlesmere (d. 1301), and fought in the English army both in France and Scotland during the later years of the reign of Edward I. In 1307 he became governor of Bristol Castle, and afterwards Edward II. appointed him steward of his household; but these marks of favour did not prevent him from making a compact with some other noblemen to gain supreme influence in the royal council. Although very hostile to Earl Thomas of Lancaster, Badlesmere helped to make peace between the king and the earl in 1318, and was a member of the middle party which detested alike Edward's minions, like the Despensers, and his violent enemies like Lancaster. The king's conduct, however, drew him to the side of the earl, and he had already joined Edward's enemies when, in October 1321, his wife, Margaret de Clare, refused to admit Queen Isabella to her husband's castle at Leeds in Kent. The king captured the castle, seized and imprisoned Lady Badlesmere, and civil war began.
After the defeat of Lancaster at Boroughbridge, Badlesmere was taken and hanged at Canterbury on the 14th of April 1322. His son and heir, Giles, died without children in 1338.