Thea is a feminine given name, from Greek Θεία, Theía, "Goddess". Other forms include Tea and Téa.

• Thea Andrews, Canadian journalist
• Thea Astley (1925–2004), Australian writer
• Thea Beckman (1923–2004), Dutch writer
• Thea Bock (1938–2025), German politician
• Thea Bowman (1937–1990), American nun
• Thea Dorn, German writer
• Thea E. Smith, American writer
• Thea Einöder, German rower
• Thea Exley (1923–2007), Australian archivist and art historian
• Thea Flaum, American TV producer
• Thea Foss (1857–1927), American entrepreneur
• Thea Garrett, Maltese singer
• Thea Gill, Canadian actress
• Thea Gilmore, British singer-songwriter
• Thea Gregory, English actress
• Thea Halo, American writer
• Thea Hochleitner (1925–2012), Austrian alpine skier
• Thea Kano, American conductor
• Thea Kellner, Romanian fencer
• Thea King (1925–2007), British clarinettist
• Thea Knutzen (1930–2016), Norwegian politician
• Tea Jorjadze or Thea Djordjadze, Georgian artist
• Thea Leitner (1921–2016), Austrian writer
• Thea Sofie Loch Næss, Norwegian actress
• Thea Muldoon (1927–2015), New Zealander first lady
• Thea Musgrave, Scottish composer
• Thea Porter (1927–2000), British fashion designer
• Thea Proctor (1879–1966), Australian artist
• Thea Rasche (1899–1971), German pilot
• Thea de Roos-van Rooden, Dutch historian and politician
• Thea Sharrock, English theatre director
• Thea Slatyer, Australian footballer
• Thea Stabell, Norwegian actress
• Thea Taylor, American singer-songwriter
• Thea Tewi (1902–1999), German-born American sculptor and lingerie designer
• Thea Tolentino, Filipina actress
• Thea Trinidad, American wrestler
• Thea Vidale, American comedian and actress
• Thea Van Seijen, Dutch singer
• Thea von Harbou (1888–1954), German filmmaker and actress
• Thea White (1940–2021), American voice actress

• Thea Fenchel, the protagonist's love interest in Saul Bellow’s The Adventures of Augie March
• Thea Queen, an incarnation of the DC Comics' superheroine Speedy played by Willa Holland on the CW's 2012 television programme Arrow
• Thea Stilton, the main protagonist in the Thea Stilton book franchise and one of the main protagonists in the Geronimo Stilton book franchise
• Thea the Thursday Fairy, from the Rainbow Magic book franchise
• Thea, a playable character in Fire Emblem Binding Blade
• Thea Brody-Daughter of Michael Brody~~Jaws 4 The Revenge
• Thea Ransome, a scientist played by Wanda Ventham in the Doctor Who story Image of the Fendahl