Hatt is a surname. Notable people with the surname include:
Richard Hatt, businessman, judge and political figure in Upper CanadaEmilie Demant Hatt (1873–1958), Danish artistGudmund Hatt (1884–1960), Danish archaeologistEliza Ruth Hatt (died 1892), mistress of William Henry Crossland and mother of his illegitimate sonJohn Hatt, travel editor of Harper's and Queen, founder in 1982 of Eland BooksRobert T. Hatt, naturalist and author, discoverer of Hatt's vesper rat