Bø is a former municipality in Telemark county, Norway. It was part of the traditional region of Midt-Telemark, but was historically regarded as part of Grenland. The 263-square-kilometre (102 sq mi) municipality existed from 1838 until its dissolution in 2020. The area is now part of Midt-Telemark Municipality. The administrative centre was the village of Bø i Telemark. Other villages in the municipality included Folkestad and Nordbøåsane.

Telemark is a county and a current electoral district in Norway. Telemark borders the counties of Vestfold, Buskerud, Vestland, Rogaland and Agder. In 2020, Telemark merged with the county of Vestfold to form the county of Vestfold og Telemark. On 1 January 2024, the county of Telemark was re-established after Vestfold og Telemark was divided again.