Eidsfjorden is a fjord in the municipalities of Bø, Hadsel, and Sortland in Nordland county, Norway. The 25-kilometre (16 mi) long fjord cuts into the island of Langøya in the Vesterålen archipelago. It branches off of the main Vesterålsfjorden. The innermost part of the fjord is part of Sortland (it was transferred from Hadsel in 1963). The west coast of the outer part belongs to Bø municipality and the eastern coast of the outer part of the fjord belongs to Hadsel.

There are two churches located along the fjord: Indre Eidsfjord Church and Ytre Eidsfjord Church (meaning "inner" and "outer" Eidsfjord churches).