John Northampton (also known as John Comberton) (died 1398) was a reformist Lord Mayor of London in 1381 and 1382, during dissension in favor of reform of its Common Council in the early years of Richard II's reign. When the oligarchic leaders of London were able to engineer the overthrow of his faction, even the book of records of reform legislation was burned. The mob politics of such radical movements increased the uneasiness of the great about allowing popular participation in government.
He had also served as Sheriff of London in 1376-77.
Northampton was raised in London, son of Thomas and Mariota Northampton. He is known to have had two brothers, William and Robert, and two sisters, Petronilla and Agnes.
He was twice married. His first wife, living in 1371, was named Johanna, his second, to whom he was married by 1375, Petronilla, daughter of John Preston and Margaret Constantine (also spelt Constantyn). By one of those marriages he left a son named James.
Northampton became alternatively known as John Comberton in the writings of chroniclers playing on the word comber (trouble) in reflection of the trouble that opponents thought his policies caused London.
Northampton came early into business in the city, being named as one of four 'upholders' of the Drapers' Guild in 1361. Outside his work he may have gained a turbulent reputation for he was bound over the keep the peace and refrain from affrays in the streets in 1365, 1369 and 1371.
He entered city politics in the Common Council as Alderman for the Cordwainer Street Ward from 1375 to 1377, and became Sheriff of the city in 1376. He became leader of the faction in the city that supported John of Gaunt and John Wycliffe, in contrast to the other party led by William Walworth and John Philipot who supported the opposition to Gaunt.
Following the Good Parliament of 1376, he was one of a cohort of Londoners who ousted Richard Lyons and others from city offices and introduced the rule that Common Council members be chosen according to craft guild affiliations rather than by city ward. In 1378 he was elected as Member of Parliament for the City in that year's parliament.