John Calley (also spelt Cawley) (1663 – May 1725, The Hague), was a metalworker, plumber and glass-blower, who became famous for being Thomas Newcomen's partner. Like Newcomen, he was a member of a Dartmouth family. He installed an early Newcomen engine at More Hall Colliery in the grounds of Austhorpe Hall in Leeds, where he is said to have become ill and died during maintenance work. However, there is also evidence that he died in The Hague in 1725, while trying to secure a foreign patent for another device.