Thorbjarnarson or Þorbjarnarson is a surname of Icelandic origin. In Icelandic names, the name is not strictly a surname, but a patronymic. Notable people with the surname include:
John Thorbjarnarson (1957–2010), Icelandic crocodilia conservationist Þórir Þorbjarnarson (Thorir Thorbjarnarson; born 1998), Icelandic basketball player