Hadsel is a municipality in Nordland county, Norway. It is part of the Vesterålen traditional region. The administrative centre of the municipality is the village of Stokmarknes, and the other village on the island of Hadseløya is Melbu. Hadsel was established as a municipality on 1 January 1838 (see formannskapsdistrikt). Sortland was separated from Hadsel in 1841.
The municipality is the southernmost municipality in the Vesterålen region. It is spread over four islands: Hadseløya, Hinnøya, Langøya, and Austvågøy. About 70% of the population live on Hadseløya island. Hadseløya island is connected to Langøya by the Hadsel Bridge. Also, the Stokmarknes Airport, Skagen, is located nearby. It is the busiest small aircraft airport in Norway, serving 100,000 passengers annually (1997).