Thea may refer to:
- Thea (award), the annual award from the Themed Entertainment Association
- Thea (TV series), a 1993 television series starring Thea Vidale and Brandy Norwood
- THEA (Texas Higher Education Assessment), a test similar to the ACT and SAT
- Thea, the former name of the tea plant genus, now included in Camellia
- Thea (name), a feminine given name
- θεά, the Greek word for goddess, the feminine of theos
- Thea, Achaea, a village in the municipal unit Messatida, Achaea, Greece
- 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 (Tampa-Hillsborough Expressway Authority), a regional expressway authority based in Hillsborough County, Florida, which includes the city of Tampa.