Gloag is a surname, and may refer to:

• Ann Gloag (born 1942), a Scottish business woman and charity campaigner
• Helen Gloag (1750–1790), of Perthshire, Scotland became the Empress of Morocco
• Helena Gloag (1909–1973), Scottish actress
• Isobel Lilian Gloag (1865–1917), English painter
• John Gloag (1896–1981), English novelist and nonfiction writer
• Joseph Gloag (ca. 1906–1977), Scottish marketing theorist and political activist
• Julian Gloag (born 1930), English novelist and screenwriter
• Paton James Gloag (1823–1906), Scottish minister and theological author
• Robin Gloag (1943–2007), one of the founders of the business that today trades as Stagecoach Group
• William Gloag (1865–1934), Scottish lawyer and academic
• William Gloag, Lord Kincairney (1828–1909), Scottish judge

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