Sir John Maunsell (c. 1195 - 1263/4), also Sir John Mansel, Provost of Beverley , was a judge and served as secretary of state and chancellor to King Henry III. In 1241, he was appointed to the vacant prebend of Thames by Henry, but Robert Grosseteste, a bishop, refused to admit him. Reportedly, he took the Thames church by force before giving up his claim to the prebend. However, he still enjoyed great secular power; the 1258 Provisions of Oxford gave four men the power to elect a council of fifteen to govern the treasury and the chancellery. These four men were the Earl Marshal (the Earl of Norfolk), Hugh Bigod, Maunsell, and the Earl of Warwick (John du Plessis ).

|- style="text-align: center;" | width="30%" |Preceded by:
Sir John Lexington | width="40%" style="text-align: center;" |Lord Chancellor
1248–1249 | width="30%" |Succeeded by:
Sir John Lexington

|- style="text-align: center;" | width="30%" |Preceded by:
Unknown | width="40%" style="text-align: center;" |Secretary of State
1253–1263? | width="30%" |Succeeded by:
Unknown