Bømlo ( /ˈbʌmˌloʊ/) is a municipality in Sunnhordland, in the southern part of the county of Hordaland, Norway. It is also the name of the main island of this archipelago, consisting of about 900 islets, located west of Stord.

The old municipality of Finnås was divided into Bømlo, Bremnes, and Moster on 1 July 1916. The two latter municipalities were merged back into Bømlo on 1 January 1963.

Bømlo was actively involved in the Shetland bus operation during the Second World War. A 23 year old male from Bømlo, Nils Nesse, was the first of the Shetland Bus men to be killed.

The municipality is named after the main island of Bømlo (Norse Bymbil), possibly derived from bembel, meaning navel or stomach. In this context, it is believed that it refers to something thick or swollen, similar to the mountain formation of Siggjo (for other possible interpretations, see Bamble). Until 1918 the name was written Bømmel.

The coat of arms was granted on 29 February 1980. Its colors include red and light grey, illustrating the leaf of a water lily interlaced with a trefoil. The trefoil symbolizes the three former municipalities Bremnes, Moster, and Bømlo, which were united in 1963. The water lily leaf, however, was simply chosen as a decorative element without any further significance.