Al(l)an or Allen Thomas may refer to:
- Alan B. Thomas Jr., businessman and American government official
- Alan G. Thomas (1911–1992), British bibliophile and Lawrence Durrell scholar
- Alan G. Thomas (scientist) (1927–2019), British materials scientist
- Alan Thomas (philosopher) (born 1964), British philosopher
- Alan Thomas (cricketer) (born 1947), former English cricketer
- Allan Thomas (born 1990), Lebanese-South African football goalkeeper
- Allen Thomas (1830–1907), Confederate States Army brigadier general
- Allen M. Thomas (born 1969), former mayor of Greenville, North Carolina
- Algy Thomas (1940–2015), Welsh rugby union player