Mandal () is a former municipality in the old Vest-Agder county, Norway. It was located in the traditional district of Sørlandet. The municipality existed from 1964 until 1 January 2020 when the municipalities of Mandal, Lindesnes, and Marnardal were merged to form a new, larger municipality of Lindesnes in what is now Agder county. Mandal was the southernmost municipality in all of Norway, with the tiny skerry of Pysen being the southernmost point of land in Norway.
The administrative centre of the municipality is the town of Mandal. The town of Mandal was the second largest town by population in the old Vest-Agder county after the nearby town of Kristiansand and it is also the fourth largest city in all of the Sørlandet/Agder region. Besides the town of Mandal, the municipality also includes the villages of Bykjernen, Skjebstad, Sånum-Lundevik, Skogsfjord-Hesland, Krossen, Harkmark, Skinsnes-Ime, and Tregde-Skjernøy.
At the time of its dissolution in 2020, the municipality is the 321st largest by area out of the 422 municipalities in Norway. Mandal is the 77th most populous municipality in Norway with a population of 15,600. The municipality's population density is and its population has increased by 9.9% over the last decade.
The river Mandalselva is a salmon river that flows through the municipality with its river mouth just outside the town. Mandal has many small, white-painted wooden houses, which is typical of towns at the South Coast of Norway (Sørlandet). The European route E39 highway connecting Kristiansand and Stavanger is the main road through Mandal. There are connecting airplane flights and ferries to Europe from Kristiansand.
The town of Mandal was established as a ladested municipality on 1 January 1838 (see formannskapsdistrikt law). On 1 July 1921, a part of the neighboring municipality of Halse og Harkmark (population: 221) that was next to the town of Mandal was merged with the town. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee.