Pettit is an English surname of Hiberno-Norman origin. Variant spellings include Pettitt and Petitt. People with the surname include:

• B. R. Pettit (1947–2006), American sculptor
• Catriona Pettit (born 1971), Australian television presenter
• George Pettit (born 1982), Canadian vocalist
• Alex Pettit (born 1986), American computer scientist, professor, and vocalist
• Lloyd Pettit (1927–2003), American sportscaster
• Thomas S. Pettit (1843–1931), newspaper publisher and politician from Kentucky
• Tom Pettit (1931–1995), American television news correspondent

• George Hamilton Pettit (1872–1953), Canadian politician
• Nathaniel Pettit (1724–1803), Upper Canada politician
• Trevor Pettit (born 1951), Canadian politician

• Albert Pettit (1930–1997), U.S. Representative from Pennsylvania
• Alex Pettit (born 1966), American public administration official
• Charles Pettit (1736–1806), American lawyer and merchant
• John Pettit (1807–1877), United States Representative and Senator from Indiana
• John U. Pettit (1820–1881), U.S. Representative from Indiana
• Milton Pettit (1835–1873), Wisconsin politician
• Thomas M. Pettit (1797–1853), politician and judge from Pennsylvania
• Thomas S. Pettit (1843–1931), newspaper publisher and politician from Kentucky
• William B. Pettit (1825–1905), American lawyer from Virginia

• Philip Pettit (born 1945), Irish philosopher and political theorist
• Thomas Pettit (mayor) (1858–1934), mayor of Nelson, New Zealand

• Becky Pettit (born 1970), American sociologist
• Donald Pettit (born 1955), American astronaut
• Edison Pettit (1889–1962), American astronomer
• Joseph M. Pettit (1916–1986), American academic
• Katherine Pettit (1868–1936), American educator
• Mary DeWitt Pettit (1908–1996), American physician
• Philip Pettit (born 1945), Irish philosopher and political theorist
• Rowland Pettit (1927—1981), American chemist
• Steve Pettit, (born 1955), President of Bob Jones University

• Bob Pettit (baseball) (1861–1910), American baseball player
• Chris Pettit (born 1984), American baseball player
• Leon Pettit (1902–1974), American baseball pitcher
• Paul Pettit (1931-2020), American baseball pitcher

• Bob Pettit (born 1932), American basketball player
• Daniel Pettit (1915–2010), English footballer and industrialist
• Nicola Pettit (born 1978), New Zealand netball player
• Sean Pettit (born 1992), Canadian freeskier
• Terry Pettit, American volleyball coach
• Tom Pettit (footballer) (1885–1970), Australian rules footballer

• Charles Pettit (1736–1806), American lawyer and merchant
• Daniel Pettit (1915–2010), English footballer and industrialist
• Gabrielle Petit (feminist) (1860–1952), French feminist activist, anticlerical, libertarian socialist, newspaper editor
• Jane Bradley Pettit, American philanthropist
• Lyman C. Pettit (1868–1950), American pastor
• Robert Lee Pettit (1906–1941), American naval enlisted man; recipient of the Navy Cross
• William H. Pettit (1885–1985), New Zealand Christian missionary

• Andy Pettitte (born 1972), American baseball pitcher