Kacenštajn Castle (Slovene: Grad Kacenštajn, German: Burg Katzenstein) comprises, together with St. Ursula's Church, the old center of the village of Begunje in the Upper Carniola region of Slovenia.

The original two-story core of the castle survives inside newer additions, as do remnants of its Gothic architecture.

The majority of the present structure dates from its Renaissance and Baroque rebuildings, and the southeast wing was added in the 19th century.

Before the Second World War, the manor served as a women's penitentiary, operated by the Sisters of St. Vincent de Paul.

In 1940, a pavilion was built in the park according to a concept by the Slovenian architect Jože Plečnik.