Heiligenkreuzkirche, Villach, Roman Catholic parish church in Perau district, Villach, Austria

Heiligenkreuzkirche is a Roman Catholic parish church in the Perau district featuring a cross-shaped floor plan with two three-story towers crowned by onion domes. The building has an octagonal central dome with cross-ribbed vaulting that gives the interior its distinctive structure.

A church of St Peter in Perau, possibly dating to the 8th century, is first mentioned in 1233; it passed to the Katharinenspital in 1244 and to Stift Griffen in 1280. The present church was built 1726–1738 to a design by Hans Eder, with Augustin Pichler, resigned abbot of Stift Griffen, as patron and Andreas Sigl as builder. It was blessed in 1744 and consecrated in 1751 by Carl Michael Count Attems, first Archbishop of Görz. The old St Peter's church was demolished in 1809.

The interior displays frescoes from the 1960s by Fritz Fröhlich featuring apocalyptic imagery, paired with a monumental high altar holding a Crucifixion group. These artistic elements shape how visitors experience the sacred space when they step inside.

The church stands on the southern bank of the Drau in Perau, with the Heiligenkreuz-Gnadenkapelle attached to the north side, reached through an oval connecting room east of the north facade tower. The oldest bell, cast by Andreas Röder in 1728, hangs in one of the two facade towers; the 900 kg Kreuzglocke and 368 kg Petrusglocke were added in 1964.

The pilgrimage church owes its origin to a legend: a crucifix was said to have been found growing out of a nearby wall, which made Perau a pilgrimage site in the 18th century. The church was consecrated in 1751 by Carl Michael Graf Attems, the first Archbishop of Gorizia.