Thomas Spencer may refer to:
- Thomas Spencer (minister) (1791–1811), English congregationalist
- Thomas Spencer (mathematical physicist) (born 1946), American mathematical physicist
- Thomas Edward Spencer (1845–1911), Australian writer
- Thomas Spencer (businessman) (1852–1905), cashier, co-founder of Marks & Spencer
- Thomas Spencer (settler) (1607–1687), early settler of Hartford, Connecticut
- Sir Thomas Spencer, 3rd Baronet (1639–1685), politician
- Thomas Spencer (MP for Southwark), MP for Southwark, 1406–1415
- Thomas Spencer (cricketer) (1850–1933), English cricketer
- Sir Thomas Spencer, 1st Baronet (1586–1622), of the Spencer baronets
- Sir Thomas Spencer, 4th Baronet (died 1722) of the Spencer baronets
- W. Thomas Spencer (born 1928), American politician
- Thomas Alfred Spencer (1860–1937), member of the Queensland Legislative Assembly
Thomas Spencer (1791–1811) was an English Congregational minister.
Thomas C. Spencer is an American mathematical physicist, known in particular for important contributions to constructive quantum field theory, statistical mechanics, and spectral theory of random operators. He earned his doctorate in 1972 from New York University with a dissertation entitled Perturbation of the Po2 Quantum Field Hamiltonian written under the direction of James Glimm. Since 1986, he has been professor of mathematics at the Institute for Advanced Study. He is a member of the United States National Academy of Sciences, and the recipient of the Dannie Heineman Prize for Mathematical Physics.
Thomas Edward Spencer was an Australian building contractor and writer.
