Heidal is a valley in Sel Municipality in Innlandet county, Norway. The U-shaped valley follows the river Sjoa which begins in the nearby Jotunheimen mountains eastward until it joins the Gudbrandsdalslågen river in the main valley which runs through the region, Gudbrandsdalen. The western end of the Sjoa river valley is in Vågå Municipality and there, it is called the Sjodalen valley. The main urban area in the valley is the village of Bjølstad (also known as Heidal). From 1908-1965, the Heidal valley was an independent municipality called Heidal Municipality, and since 1965, it has been a part of Sel Municipality.
The valley runs northwest from the village of Sjoa for about 16 kilometres (9.9 mi) to the village of Bjølstad where the valley curves to the southwest/south for about 15 kilometres (9.3 mi) before entering Vågå Municipality. After entering Vågå, the valley becomes much narrower as it enters into the Jotunheimen mountains and heading to the source of the river, the large lake Gjende.