Basilika Sonntagberg, Catholic pilgrimage church in Sonntagberg, Austria.

The Basilika Sonntagberg is a Baroque church with a double-tower facade on a 712-metre ridge. Its concave two-storey west front stands between three-storey towers capped by curved tent roofs with onion finials. The nave has high arched windows and a transept with rounded corners; the rectangular choir carries a bell turret with a curved hood and lantern.

The site began in 1440 as a small chapel built by Abbot Benedict I from Seitenstetten Abbey. Over time it grew in importance and received its Trinity dedication in 1477, marking its rising status as a pilgrimage destination.

The name Sonntagberg ("Sunday Mountain") refers to the Sunday devotions held on the ridge. A confraternity was founded in 1651, and annual pilgrimages grew from 1666. A copper plate with a Holy Trinity image was fixed to the Zeichenstein, a large natural stone linked to the founding legend of a shepherd's dream, in 1614.

The church stands on a paved plateau ringed by a gallery with drainage and ventilation channels; the main west facade is reached by a representational stairway with iron grilles. The choir connects to the rectory by a first-floor passage over a round-arched bridge. The plateau is level once you are up, so the climb is concentrated at the entrance side.

The high altar holds the Gnadenstuhl, a Trinity group, and the facade above the clock carries statues of Archangel Michael flanked by Saints John and Paul, carved by Peter Widerin in 1719. The main portal's iron plate door is decorated with figures known as Türkin and Türke.