John Trelawny may refer to:
- John Trelawny I (fl. 1397), MP for Bodmin (UK Parliament constituency) in 1397, father of John Trelawny II
- John Trelawny II (fl. 1413–1421), MP for Cornwall (UK Parliament constituency) 1413–1421, son of John Trelawny I
- John Trelawny III (fl. 1421–1449), MP for Liskeard (UK Parliament constituency) 1421 and Lostwithiel (UK Parliament constituency) 1449
- John Trelawny (died 1563), Member of Parliament (MP) for Liskeard
- John Trelawny (died 1568), his son, High Sheriff of Cornwall
- Sir John Trelawny, 1st Baronet (1592–1664), Royalist before and during the English Civil War
- John Trelawny (died 1680), MP for West Looe
- John Trelawny (died 1682), MP for West Looe (UK Parliament constituency)
- John Trelawny (1633–1706), MP for Plymouth (UK Parliament constituency)
- Sir John Trelawny, 4th Baronet (1691–1756), MP for East Looe, West Looe and Liskeard
- Sir John Salusbury-Trelawny, 9th Baronet (1816–1885), MP for Tavistock and Eastern Cornwall