John Shackleton (died 16 March 1767) was a British painter and draughtsman who produced history paintings and portraits.
Shackleton painted several surviving portraits, for example of Henry Pelham (National Portrait Gallery), William Windham (1717–1761; now at Felbrigg Hall, Norfolk), and of John Bristowe, steward to the first duke of Newcastle (now in the Reitlinger Museum of Fine Art, Maidenhead).
On 8 March 1758 he was elected to be a member of the Society for the Encouragement of Arts, Manufactures, and Commerce, then in its infancy.
]ossie of Wardour Street, Soho’, and ‘a half-length picture of a Lady by Vandyke and a small landscape by Gaspar Poussin to John Bristow Esqr Keeper of His Majesties Lions in the Tower’.
On 25 October 1742 (as a parishioner of St George's, Hanover Square, London) he married Mary Ann Regnier.