Sveio is a municipality in Vestland county, Norway. Sveio is a border district that is sometimes considered to be located in the traditional district of Haugalandet since it is located on the Haugalandet peninsula, but it is also considered to be in the traditional district of Sunnhordland since it is located in southern Hordaland county. The administrative centre of the municipality is the village of Sveio. Other villages in the municipality include Auklandshamn, Førde, Våga, and Valevåg.

The 246-square-kilometre (95 sq mi) municipality is the 290th largest by area out of the 356 municipalities in Norway. Sveio is the 165th most populous municipality in Norway with a population of 5,732. The municipality's population density is 25.6 inhabitants per square kilometre (66/sq mi) and its population has increased by 6.1% over the previous 10-year period.

Sveio is the site of the Ryvarden Lighthouse which marks the western entrance to the Hardangerfjorden. The lighthouse is automated and the old keepers house and building have now been converted into art galleries, the Flókemuseum, and a cafe. The composer Fartein Valen lived much of his life in Valevåg in northern Sveio. Valenheimen, the house he lived in is open to the public and the Fartein Valen Festival is held annually in Sveio.

The Triangle Link bridge-tunnel network is based in northern Sveio, connecting the islands to the north to the mainland. The southern entrance to the Bømlafjord Tunnel is located along the European route E39 highway, just south of the village of Valevåg.

The municipality of Sveio was established in 1865 when the part of Finnås municipality located south of the Bømlafjorden (population: 2,227) and the Vikebygd part of the municipality of Fjelberg (population: 1,062) were joined as the new municipality of Sveen (later the spelling was changed to Sveio). On 1 January 1902, the Vikebygd area (population: 1,092) was separated from Sveio to form its own municipality.

During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1964, Sveio (population: 1,697) was merged with the neighboring municipality of Valestrand (population: 1,216), the western half of the municipality of Vikebygd (population: 471), and a small part of the municipality of Skjold (population: 24). The part of Skjold was transferred from Rogaland county to Hordaland county on the same date.

The municipality (originally the parish) is named after the old Sveio farm (Old Norse: Svíða) since the medieval Sveio Church was built there. The name is identical with the word svíða which means "to singe" or "to burn", referring to an area that was cleared by burning. Historically, the name of the municipality was spelled Sveen. On 1 December 1911, a royal resolution changed the spelling of the name of the municipality to Sveio.

The coat of arms was granted on 19 February 1982. The official blazon is "Gules, a fleur-de-lis cleft argent." (Norwegian: På raud grunn ei kløyvd kvit lilje). This means the arms have a red field (background) and the charge is a split fleur-de-lis. The charge has a tincture of argent which means it is commonly colored white, but if it is made out of metal, then silver is used. The arms are derived from the historic arms of Jon Gauteson from Sveio, who lived around the year 1500. His family became Norwegian nobility in 1591, and he was the first in his family to use this symbol as part of his arms. The municipal arms were designed by Kolbjørn Ekkje. The municipal flag has the same design as the coat of arms.