Hatt is a surname. Notable people with the surname include:
Richard Hatt, businessman, judge and political figure in Upper Canada
Emilie Demant Hatt (1873–1958), Danish artist
Gudmund Hatt (1884–1960), Danish archaeologist
Eliza Ruth Hatt (died 1892), mistress of William Henry Crossland and mother of his illegitimate son
John Hatt, travel editor of Harper's and Queen, founder in 1982 of Eland Books
Robert T. Hatt, naturalist and author, discoverer of Hatt's vesper rat
