Þórarinsdóttir is an Icelandic surname. Notable people with the surname include:
Arndís Þórarinsdóttir (born 1982), Icelandic children's author Brynhildur Þórarinsdóttir (born 1970), Icelandic children's writer Steinunn Þórarinsdóttir (born 1955), Icelandic sculptor