John Pratt may refer to:

• John Pratt (judge) (1657–1725), Lord Chief Justice of England and interim Chancellor of the Exchequer
• John Pratt (soldier) (1753–1824), United States Army officer
• John Pratt, 1st Marquess Camden (1759–1840), British politician
• John Pratt, 3rd Marquess Camden (1840–1872), British politician
• John Pratt, 4th Marquess Camden (1872–1943), British peer
• John Pratt (died 1835), hanged for sodomy
• John Pratt (archdeacon of Calcutta) (1809–1871), British clergyman and mathematician, developer of the theory of isostasy
• John Pratt (cricketer) (1834–1886), English cricketer
• John Teele Pratt (1873–1927), American corporate attorney, philanthropist, music impresario, and financier
• John Pratt (Liberal politician) (1873–1952), Scottish Liberal politician
• John Lee Pratt (1879–1975), American businessman who served on GM's board of directors
• John Pratt (Canadian politician) (1894–1973), Manitoban politician
• John H. Pratt (1910–1995), US Court of Appeals judge
• John Pratt (Provost of Southwell) (1913–1992), Anglican archdeacon and provost
• John Winton or John Pratt (1931–2001), English naval officer, author and obituarist
• John W. Pratt (born 1931), professor of statistics, economics, and business at Harvard University
• John Pratt (footballer) (born 1948), English footballer
• John Bridge Pratt (1833–1870), husband of Anna Bronson Alcott Pratt, the elder sister of novelist Louisa May Alcott
• John G. Pratt (1816–1866), Confederate general from Louisiana
• John M. Pratt (1886–1954), tax resistance leader, activist, publicist and newspaper man
• John S. Pratt (1931–2020), American Army drum instructor
• John Jonathon Pratt (1831–1905), American journalist and newspaper editor
• John Pratt (archdeacon of St David's), Welsh Anglican priest