Thomas, Tom, or Tommy Harrison may refer to:
Arts and entertainment
T. Alexander Harrison (1853–1930), American artist
Thomas Erat Harrison (1858–1917), English artist
Tom Harrison (musician) (born 1985), British jazz musician
Business and industry
Thomas Harrison (architect) (1744–1829), English architect and bridge engineer
Thomas Elliot Harrison (1808–1888), English civil engineer
Thomas Harrison (ship-owner) (1815–1888), English ship-owner
Thomas Harrison (surveyor) (c. 1823–1894), surveyor in Jamaica
Law and politics
Thomas W. Harrison (1856–1935), U.S. representative from Virginia (second name Walter; had a cousin Thomas Willoughby Harrison (1824–1910) West Virginia judge
Tom Harrison (Australian politician) (1864–1944), Australian politician
Tom Harrison (American politician) (1939–2024), American politician
Military
Thomas Harrison (soldier) (1606–1660), English soldier, sided with Parliament in the English Civil War
Thomas Harrison (British Army officer) (1681 – before 1755), British Army officer and politician
Thomas Harrison (general) (1823–1891), Confederate States Army brigadier general, district judge
Thomas Sinclair Harrison (1898–?), South African World War I flying ace
Sports
Thomas Harrison (footballer) (1867–1942), English footballer for Aston Villa
Tommy Harrison (1892–1931), English boxer
Thomas Harrison (cyclist) (born 1942), Australian cyclist
Tom Harrison (baseball) (1945–2023), American baseball pitcher
Tom Harrison (cricketer) (born 1971), English cricketer
Tommy Harrison (footballer) (born 1974), Scottish footballer for Heart of Midlothian
Others
Thomas Harrison (translator) (1555–1631), English Puritan scholar and a translator for the King James Version of the Bible
Thomas Harrison (minister) (1619–1682), English nonconformist minister, active in Virginia and Ireland