Þórbergur Þórðarson (Thórbergur Thórdarson) (Hali í Suðursveit, 12 March 1888/1889– Reykjavík 12 November 1974) was an Icelandic author and Esperantist.
An ironist, satirist, volatile critic, and ground-breaking achiever in experimental auto-fiction, Þórbergur arguably remains among Iceland's most beloved 20th century authors. He is considered one of the greatest Icelandic stylists of his day, with an unrivalled vocabulary and astonishing facility for written expression. Therefore he was respectfully dubbed "Maestro Þórbergur".
Þórbergur was an autodidact. As recounted in his largely autobiographical works, Íslenzkur aðall (1938) and Ofvitinn (1940), Þórbergur lived in poverty for much of his youth and early adulthood and could not afford secondary or higher education.