Arna is a former municipality in the old Hordaland county, Norway. The municipality existed from 1964 until 1972. It encompassed the northeastern part of the Bergen Peninsula, along the Sørfjorden, bordering the city of Bergen across the mountains to the west. The administrative centre of the municipality was the village of Indre Arna. The municipality stretched from the village of Ytre Arna to Trengereid along the coast and then inland about 8 kilometres (5.0 mi) to the Espeland area.^[1] Today, the area of the former municipality makes up the borough of Arna in the city of Bergen.

On 1 January 1964, the historic municipality of Haus was split into two parts. The part on the island of Osterøy became part of the new municipality of Osterøy. The rest of Haus, located on the Bergen Peninsula became the municipality of Arna. The municipality was short-lived due to its proximity to the growing city of Bergen. On 1 January 1972, Arna was merged into the city of Bergen (along with the other neighboring municipalities of Fana, Laksevåg, and Åsane). Upon its dissolution in 1972, Arna had 11,766 residents.^[3]

During its existence, this municipality was governed by a municipal council of directly elected representatives. The mayor was indirectly elected by a vote of the municipal council.^[5]

• List of former municipalities of Norway