Songdalen is a former municipality in the old Vest-Agder county, Norway. The municipality existed from 1964 until 2020 when it was merged with Søgne and Kristiansand municipalities to form a new, much larger Kristiansand municipality in what is now Agder county. It was located in the traditional district of Sørlandet, just outside of the city of Kristiansand. The administrative centre of the municipality was the village of Nodeland. Other villages in the municipality included Brennåsen, Finsland, Kilen, Nodelandsheia, and Volleberg. The Sørlandsbanen railway line ran through the municipality, stopping at Nodeland Station. The European route E39 highway also ran through the southern part of the municipality.

Prior to its dissolution in 2020, the 216-square-kilometre (83 sq mi) municipality is the 323rd largest by area out of the 422 municipalities in Norway. Songdalen is the 161st most populous municipality in Norway with a population of 6,568. The municipality's population density is 31.8 inhabitants per square kilometre (82/sq mi) and its population has increased by 16% over the last decade.

Songdalen was a relatively short-lived municipality. During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1964, the municipality of Greipstad (population: 2,061), most of the municipality of Finsland (population: 797) except for the Kleveland bru area, and the Eikeland area of Øvrebø (population: 39) were all merged to form the new municipality of Songdalen. On 1 January 1978, a small area of Vennesla municipality (population: 10) was transferred to Songdalen. Then on 1 January 1984, the unpopulated Hauglandsvatnet area was transferred from Vennesla to Songdalen.

On 1 January 2020, the three neighboring municipalities of Kristiansand, Songdalen, and Søgne merged to form one large municipality called Kristiansand.

The municipal name is relatively new, having been created in 1964. The name comes from the local river Songdalselva (Old Norse: Sygna). The lower part of this river is also known as the Søgneelva. The first element of the name comes from the Old Norse name for the river. The river name is derived from the verb súga which means "to suck". The last element is dalr which means "valley" or "dale".

The coat of arms was granted on 20 December 1985 and they were in use until the municipality was dissolved on 1 January 2020. The official blazon is "Vert, three oak leaves in pall and three acorns in pall inverted stems conjoined Or" (Norwegian: I grønt tre gull eikeblad i trepass med eikenøtter mellom). This means the arms have a green field (background) and the charge is three conjoined oak leaves with three acorns. The charge has a tincture of Or which means it is commonly colored yellow, but if it is made out of metal, then gold is used. The green color in the field and the oak leaf and acorn design symbolize the importance of the abundant oak forests in the municipality. There are three leaves/acorns to represent each of the three former municipalities of Greipstad, Finsland, and Øvrebø which were merged to form the municipality of Songdalen in 1964. The arms were designed by Nils Th. Finstad.

The Church of Norway has two parishes (sokn) within the municipality of Songdalen. It is part of the Mandal prosti (deanery) in the Diocese of Agder og Telemark.

Songdalen was an inland municipality, the municipalities of Kristiansand and Vennesla were located to the east, Marnardal to the west, and Søgne to the south. Songdalen's administrative centre, Nodeland, is a short 10-minute drive from the center of the city of Kristiansand.