Fujiwara is one of the four major family names (Minamoto, Taira, To (or Fujiwara) and Tachibana), and the Fujiwara family, also known as the To clan, was the earliest member of the Fujiwara clan.
源氏・平氏・藤・橘氏のいわゆる四姓の一つであり、藤原氏はその筆頭名門氏族であり、藤氏（とうし）とも略称した。