Pfarrkirche Untersiebenbrunn, Catholic parish church in Untersiebenbrunn, Austria

The Pfarrkirche Untersiebenbrunn stands on a terrace north of the village, surrounded by a walled former fortified churchyard with a two-storey gate tower. The Baroque building, designed by Johann Koch after the medieval fortified church was demolished in 1709, has a Romanesque masonry core. Its three-storey west tower facade features a volute gable, a bell storey with crowned sound windows and an onion dome; the long nave has round-arched windows and a surrounding cornice.

The original building was a medieval fortified church that was demolished in 1709 and reconstructed in 1710 according to plans by architect Johann Koch. This rebuilding established the structure's current form.

The parish, founded in 1784, is incorporated into Melk Abbey, whose coat of arms appears above the portal of the small triangular-gabled porch on the south side of the nave. The pulpit, carved in the mid-18th century, was transferred here in 1910 from the parish church of Melk.

The church maintains regular services as an active parish within the Gänserndorf deanery of the Archdiocese of Vienna. Visitors can attend services during scheduled times.

The fortified churchyard still preserves remains of its ramparts and gate tower, and the church hill conceals Erdställe — hidden crawl passages — and an emergency well. The gate tower was later raised to two storeys and given a triangular gable.