William Morison (1663–1739), of Prestongrange, Haddington, was a Scottish politician who sat in the Parliament of Scotland from 1690 to 1707 and in the British House of Commons as a Whig between 1707 and 1715. Morison died abroad in 1739, leaving many creditors. He and his first wife had five sons, of whom only one survived, and three daughters - their son received his mother’s inheritance of Craigleith. The rest of Morison’s property including the saltworks at Morison’s Haven and Prestongrange were sold off.