Douglas Garven Alexander (born 26 October 1967) is a British Labour politician who was the Shadow Foreign Secretary and former Member of Parliament (MP) for Paisley and Renfrewshire South.

Alexander or Alex Douglas may refer to:

• Alexander Douglas (cleric) (fl. 1528), Scottish noble and cleric, Bishop-elect of Moray
• Alexander Douglas (bishop) (died 1623), Roman Catholic Bishop of Moray, Scotland
• Sir Alexander Douglas (Orkney and Shetland) (died 1718), Member of Parliament for Orkney and Shetland, 1708–1713
• Alexander Douglas-Hamilton, Marquess of Douglas and Clydesdale (born 1978), Scottish aristocrat
• Alexander Edgar Douglas (1916–1981), Canadian physicist
• Alex Douglas (politician) (born 1958), Queensland Member of Parliament for Gaven
• A.S. Douglas (Alexander Shafto Douglas, born 1921), British professor of computer science
• Alex Douglas, character in The Ambassador (1984 American film)