Donald Thomas or Don Thomas may refer to:
- People
- Donald A. Thomas (born 1955), American engineer and former NASA astronaut
- Donald Michael Thomas (born 1935), Cornish novelist, poet, and translator
- Donald Serrell Thomas (born 1926), British writer
- Donald Thomas (athlete) (born 1984), Bahamian high jumper
- Donald Thomas (American football) (born 1985), American football guard
- Donnie Thomas (American football), American football linebacker chosen in the 1976 NFL Draft
- Donald Thomas (racing driver), former NASCAR Cup Series driver
- Donald W. Thomas (1953–2009), university administrator and ecologist
- E. Donnall Thomas (1920 – 2012), American physician, developer of bone marrow transplant
- Fiction
- Don Thomas of Blue Streak (comics)