Sandefjord is a town and municipality in Vestfold and Telemark, and is by population the largest municipality in the county. Sandefjord center is located at the end of the Sandefjord fjord. With the peninsulas Østerøya and Vesterøya, the municipality has a coastline of about 160 km.

The municipality borders in the north to Tønsberg and Larvik, in the west to Larvik and in the east to Tønsberg, Tønsbergfjorden and Færder. Sandefjord has a small exclave, Himberg, which is surrounded by Larvik just by the municipal border. Sandefjord municipality includes the town of Sandefjord, and the settlements Sandefjord (with 44,968 inhabitants), Andebu (2,442 inhabitants), Kodal (1,039 inhabitants), Høyjord (385 inhabitants), Stokke (3,918 inhabitants), Fossnes (538 inhabitants), Melsomvik (2,054 inhabitants), Brunstad (262 inhabitants) and parts of Sem (45 of a total of 2,664 inhabitants) 1 January 2020.

The Vestfold line and Europavei 18 pass through the municipality. The ferry companies Color Line and Fjord Line operate ferry routes to Strömstad in Sweden, and Sandefjord Airport, Torp has air connections to national and international destinations. Sandefjord is known for shipping, shipbuilding, whaling and the chemical industry. The municipality is also known for housing the remains of a town from the weighting period in the form of Gokstadhaugen and associated house foundations and streets. The Gokstad ship was found in 1880.

Sandefjord municipality includes several former municipalities. On 1 January 1968, the municipality of Sandar was incorporated into Sandefjord through a municipal merger, and on 1 January 2017, the municipalities of Stokke (with the exception of the Vear area) and Andebu were incorporated into Sandefjord as part of the municipal reform. At the same time, Sandefjord's municipality number was changed from 0706 to 0710, and the municipality received a new municipal coat of arms.

Sandefjord is known for shipping and the chemical industry. History from shipbuilding and whaling was reflected in the local business community, including Jahre's oil and grease industry, Framnæs Mechanical Workshop and Jotun paint factory. Jotun is today the largest company in Sandefjord.