Sir William Douglas, 4th Baronet ( â 16 May 1783) was a British politician who represented Dumfries Burghs in the House of Commons of Great Britain from 1768 to 1780.
The son of Sir John Douglas, 3rd Baronet and his wife, Christian Cunningham, daughter of Sir William Cunningham, 2nd Baronet, he was a descendant of Lady Catherine Douglas, sister of William Douglas, 1st Duke of Queensberry.
Sir William was educated at Glasgow University.
He served as Member of Parliament for Dumfries Burghs between 1768 and 1780. He succeeded his uncle Charles Douglas, a wealthy East India Company merchant to his Breconwhat estate in Dumfries in 1770. Sir William later commissioned the building of Lockerbie House. He was also a favourite of his relative the Duke of Queensberry, who bequeathed to him ã16,000 upon his death in October 1778.
On 21 March 1772, Douglas was married to Grace Johnstone, a daughter of William Johnstone. Together, they were the parents of five sons and four daughters, including:
Sir William died on 16 May 1783.