Houstoun is a surname. Notable people with the surname include:
John Houstoun (1744 – 1796), American lawyer and statesman from Savannah, GeorgiaDr. William Houstoun (botanist) (1695–1733), British surgeon and botanistWilliam Houstoun (lawyer) (1755–1813), American lawyer, Continental Congressman for GeorgiaSir William Houstoun (fl. 1830s), British army officer, Governor of Gibraltar