Harðarson is an Icelandic surname meaning son of Hörður. In Icelandic names, the name is not strictly a surname, but a patronymic. Notable people with the surname include:
Bjarni Harðarson (born 1961), Icelandic politician Falur Harðarson (born 1968), Icelandic basketball player and coach Ísak Harðarson (1956–2023), Icelandic poet and translator Jóhannes Harðarson (born 1976), Icelandic football coach and former player Kristján Harðarson (born 1964), Icelandic long jumper
Similar name for a daughter is Harðardóttir.