Haltdalen is a former municipality in the old Sør-Trøndelag county, Norway. The 509-square-kilometre (197 sq mi) municipality existed from 1838 until 1972 when it was merged with Ålen Municipality to become the present-day Holtålen Municipality in Trøndelag county. The administrative centre of the municipality was the village of Haltdalen where the Haltdalen Church is located.