Thea may refer to:

  • Thea (name), a feminine given name
  • An alternative spelling of Theia, a figure in Greek mythology
    • Theia (planet), a Mars-sized protoplanet that may have been involved in the creation of the Moon
  • Thea, the former name of the tea plant genus, now included in Camellia
  • Thea, Achaea, a village in the municipal unit Messatida, Achaea, Greece
  • Transgender Health & Educational Alliance (THEA) Atlanta, Ga
  • Thea (award), the annual award from the Themed Entertainment Association
  • Thea (TV series), a 1993 television series starring Thea Vidale and Brandy Norwood
  • Texas Higher Education Assessment, a test similar to the ACT and SAT
  • Tampa-Hillsborough Expressway Authority, a regional expressway authority based in Hillsborough County, Florida
  • Another word for the mythological animal theow