Austad is a former municipality of the former Vest-Agder county, Norway. The 44-square-kilometre (17 sq mi) municipality existed from 1909 until its dissolution in 1963. The municipality encompassed the area surrounding the Rosfjorden in the southern, coastal part of the present-day municipality of Lyngdal. The administrative centre of the municipality was the village of Austad where Austad Church is located.

Vest-Agder was one of 18 counties (fylker) in Norway up until 1 January 2020, when it was merged with Aust-Agder to form Agder county. In 2016, there were 182,701 inhabitants, around 3.5% of the total population of Norway. Its area was about 7,277 square kilometres (2,810 sq mi). The county administration was located in its largest city, Kristiansand.