Hornindal is a former municipality in Sogn og Fjordane county, Norway. The 187-square-kilometre (72 sq mi) municipality existed from 1867 until 1965 and then again from 1977 until its dissolution in 2020. It was located in the traditional district of Nordfjord. The area is now part of Volda Municipality in Møre og Romsdal county. The administrative centre was the village of Grodås. The municipality was located at the eastern end of the lake Hornindalsvatnet, the deepest lake in Northern Europe. The rest of the lake lies inside neighboring Eid Municipality.

Prior to its dissolution in 2020, the 187-square-kilometre (72 sq mi) municipality was the 336th largest by area out of the 422 municipalities in Norway. Hornindal Municipality was the 382nd most populous municipality in Norway with a population of about 1,152. The municipality's population density was 7 inhabitants per square kilometre (18/sq mi) and its population had decreased by 5.8% over the previous 10-year period.

The European route E39 highway passed through Hornindal Municipality as it made its way along the western coast of Norway. The Kviven Tunnel was completed in 2012 as part of the new E39 route connecting Hornindal to Volda Municipality in Møre og Romsdal county to the north. The tunnel was constructed to avoid the ferry crossing over the Voldsfjorden and it shortened the distance from Hornindal to Volda significantly.

Since ancient times, Hornindal was a sub-parish (sokn) of the Eid prestegjeld (see formannskapsdistrikt law). In 1865, Hornindal became a separate Church of Norway parish. On 1 January 1867, Eid Municipality was divided into two: the eastern part (population: 1,612) became the new Hornindal Municipality and the western part (population: 2,918) remained as (a smaller) Eid Municipality.

During the 1960s, there were many municipal mergers across Norway due to the work of the Schei Committee. On 1 January 1965, Hornindal Municipality was dissolved and its lands were divided. The villages of Navelsaker and Holmøyvik and all of the old Hornindal Municipality located west of those villages (population: 310) was transferred to Eid Municipality. The eastern part of the old Hornindal Municipality (population: 1,184) became part of Stryn Municipality.

The dissolution of Hornindal Municipality was not long-lasting due to discontent among the population. On 1 January 1977, the area of the old Hornindal Municipality that had joined Stryn Municipality in 1965 (population: 1,202) was separated from Styrn and recreated as a separate Hornindal Municipality once again. The portions of the old Hornindal Municipality that were merged into Eid Municipality in 1965 remained a part of Eid Municipality.

On 1 January 2019, the Maurset area in southern Hornindal Municipality (population: 19) was transferred to the neighboring Stryn Municipality.

On 1 January 2020, all of Hornindal Municipality (in Sogn og Fjordane county) merged with the neighboring Volda Municipality and became part of Møre og Romsdal county.