Askøy is a municipality in the county of Hordaland, Norway. Since the opening of the Askøy Bridge leading to the mainland in Bergen in 1992, the population has increased rapidly. Its population growth is as of 2008 among the highest in Norway. Most of the population growth is due to immigration from Bergen, Nordhordland and Midhordland.

The first element is the name Askøy came from the farm Ask (Old Norse: Askr) and the last element is øy, meaning "island". The name of the farm is identical with the word askr, meaning "ash tree". Until 1918 the name was written "Askøen".

The coat-of-arms was granted on 28 September 1961. The arms are a canting showing an ash tree (aske) on an island (øy) with waves of the sea in the base of the shield.

The parish of Askøen was established as a municipality on 1 January 1838 (see formannskapsdistrikt). Laksevåg was separated from Askøy on 1 July 1918. Most of Herdla was merged with Askøy on 1 January 1964.

Askøy is home to several sports teams. Askøy Fotballklub is an association football club, formed in 1999 by the merger of Florvåg Idrettsforening and Kleppestø Fotball. The club has a large number of teams, of which the majority are junior football teams. The men's senior team plays in the Norwegian third division as of 2008. The oldest sports club on the island is Ask Idrettslag, mainly an athletics club, founded in 1928.