Osafjord or Osafjorden is a fjord arm that branches off of the main Hardangerfjord in Hordaland county, Norway. Fully located within Ulvik municipality, the fjord is long. The small village of Osa lies at the end of the fjord. The outermost part of the fjord is known as Bagnsfjorden, named after the headland where the fjord starts. The Ulvikafjorden branches off of the Osafjorden to the north.