Sir John Stepney, 3rd Baronet (1618 – c. 1676) was a Welsh politician who sat in the House of Commons from 1640 to 1643.
Stepney was the son of Sir John Stepney, 1st Baronet, and his wife Jane Mansel, daughter of Sir Francis Mansel of Muddlescomb, Carmarthenshire.
He was elected MP for Haverfordwest for the Long Parliament in November 1640 and held the seat until he was disabled from sitting in 1643.
[2] He remained loyal to the king and was governor of the town of Haverfordwest during the Civil War.
He was captured by the Parliamentary forces at Hereford on 18 December 1645 and imprisoned.