Sirdal is a municipality in Agder county, Norway. It is located in the northwestern part of the traditional district of Lister. The administrative centre of the municipality is the village of Tonstad. Other villages in Sirdal include Bjørnestad, Haughom, Kvæven, Lunde, and Tjørhom.

Bakke is a former municipality in Vest-Agder county, Norway. The 244-square-kilometre (94 sq mi) municipality existed from 1838 until its dissolution in 1965. It was located in the present-day municipalities of Sirdal and Flekkefjord. It included the whole Sirdalen valley along the Rogaland county border, stretching from the Aust-Agder county border in the north to Sirnes and the lake Lundevatnet in the south. The administrative center was the village of Sira where Bakke Church is located.