Sir Roger Brabazon (c. 1247 – 13–14 June 1317) was an English lawyer, and Chief Justice of the King's Bench from 1296 to 1316.
In 1290, after Ralph de Hengham had been dismissed from the King's Bench, Brabazon was hired as a junior justice.
In 1291–1292, Brabazon took part in hearing the 'Great Cause' concerning Edward I's overlordship over Scotland, and pronounced the judgement in favour of John Balliol as heir to the Scottish crown.
Upon the death of Gilbert de Thornton in 1295, Brabazon was then appointed Chief Justice of the King's Bench, a position he held until old age and infirmity forced him to resign in 1316.
He was buried in St Paul's Cathedral, and his London house was sold to Hervey de Stanton, later a Chief Justice of the King's Bench himself.