Wildalpen is a municipality in the district of Liezen, in the Austrian state of Styria. It lies in the Salza valley, a side valley of the Enns, in the mountainous region of Upper Styria near the border with Lower Austria.
The municipality is sparsely populated, with a population of 432 as of 2025. It is known for its alpine setting, with extensive forests and the clear waters of the Salza river, a tributary of the Enns noted for its karst springs and its popularity for fishing and kayaking.
Wildalpen is also the site of a historic water-supply system: since the late nineteenth century, springs in the area have supplied drinking water to the city of Vienna through a pipeline, a function that remains in use today.