Alexander Stewart may refer to:
- Alexander Stewart (British Army officer) (c. 1739–1794), British army general, Scottish politician, MP for Kirkcudbright Stewartry 1786–94
- Alexander Stewart (1746–1831), Irish MP
- Alexander Stewart (Nova Scotian politician) (1794–1865), lawyer, judge and politician in Nova Scotia
- Alexander Robert Stewart (1795–1850), Irish MP
- Alexander Stewart (American politician) (1829–1912), US politician
- Alexander David Stewart (1852–1899), Canadian politician
- Alexander Stewart (British Columbia politician), mayor of Victoria, British Columbia from 1914 to 1916
- Alexander Stewart (MSP) (born 1962), Conservative Member of the Scottish Parliament
- Alexander Stewart, 4th High Steward of Scotland (died 1283), Scottish magnate
- Alexander Stewart of Bonkyll (c. 1271–1319), Scottish nobleman
- Alexander Stewart, Earl of Buchan (1343–1405), also known as the "Wolf of Badenoch", Scottish prince and magnate
- Alexander Stewart, Earl of Mar (1375–1435), Scottish nobleman
- Alexander Stewart, Duke of Rothesay (1430–1430)
- Alexander Stewart, Duke of Albany (c. 1454–1485), Scottish prince and magnate
- Alexander Stewart, 2nd Earl of Buchan (died 1505)
- Alexander Stewart, Duke of Ross (1514–1515)
- Alexander Stewart, 1st Earl of Galloway (1580–1649)
- Alexander Stewart, 6th Earl of Galloway (c. 1694–1773)
- Alexander Stewart (1699–1781) (1697/99–1781), ancestor of the Marquess of Londonderry