Árnadóttir is an Icelandic patronymic, used by:
- Ásta Árnadóttir (born 1983), Icelandic former footballer who was a defender
- Bergþóra Árnadóttir (1948–2007), Icelandic folk song composer and singer
- Guðbjörg Aradóttir, Icelandic entomologist
- Halla Margrét Árnadóttir (born 1964), Icelandic singer, represented Iceland in the Eurovision Song Contest 1987
- Nína Björk Árnadóttir (1941–2000), Icelandic playwright, poet, and novelist
- Ragna Árnadóttir (born 1966), Icelandic lawyer and former Minister of Justice and Ecclesiastical Affairs of Iceland
- Ragnheiður Elín Árnadóttir (born 1967), Icelandic politician, the Minister of Industry and Commerce since 23 May 2013