Herdla is a former municipality in the old Hordaland county in Norway. The municipality existed from 1871 until its dissolution in 1964. The municipality encompassed a large group of about 2,000 islands and skerries covering about of land area, to the northwest of the city of Bergen in what is now parts of Øygarden, Alver, and Askøy municipalities in Vestland county. The administrative centre of the municipality was the small island-village of Herdla. The municipality included the northern third of the island of Holsnøy, the northern third of the island of Askøy, and the islands of Misje, Turøy, Toftøy, Rongøy, Blomøy, Ona, Bognøy, and many smaller surrounding islands.
On 1 January 1871, the western island district of the municipality of Manger was separated to form the new municipality of Herlø (an old spelling that was changed to Herdla in 1917). Initially, the municipality had 2,484 residents. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. In January 1964, the municipality of Herdla was dissolved and its land was split up as follows:
the islands of Misje and Turøy (population: 404) became part of Fjell Municipality
the island of Herdla and all of Herdla on the island of Askøy (population: 1,564) became part of Askøy Municipality
all of Herdla on the island of Holsnøy (population: 811) became part of Meland Municipality
all of Herdla located west of the Hjeltefjorden (population: 2,131) became part of Øygarden Municipality
the island of Bognøy (population: 29) became part of Radøy Municipality
The municipality (originally the parish) is named after the old Herlø farm (Herðla) since the first Herdla Church was built there. The meaning of the name is uncertain. One possibility is that it is derived from hǫrðar which is the old name for a person from medieval Hordaland. Another possibility is that it means "to split" or "to divorce", likely referring to the fact that the island on which the farm is located is separated from Askøya by the narrow Herdlesundet strait.