Bíldudalur is a village situated on the coast of Arnarfjörður, one of the Westfjords in Iceland.

It is situated in the Vesturbyggð municipality and has 166 inhabitants (as of January 2011).

The village prospered in the 19th century thanks to sound business enterprise and the booming fishing industry. Ólafur Thorlacius (1761–1815) set up business in Bíldudalur following the end of the Danish trade monopoly. He was one of the most influential businessmen in Iceland at the beginning of the 19th century. He bought and sold fish, traded goods and ran his own small fishing fleet. One of his successors, Pétur J. Thorsteinnsson (1854–1924) successfully continued this operation.