'Abbey of the Holy Cross') is a Cistercian monastery in the village of Heiligenkreuz in the southern part of the Vienna woods, c. 13 km north-west of Baden in Lower Austria.

Heiligenkreuz was richly endowed by the founder's family, the Babenberg dynasty, and was active in the foundation of many daughter-houses.

In the latter, Turkish soldiers burnt down much of the abbey precinct, which was rebuilt on a larger scale in the Baroque style under Abbot Klemens Schäfer.

Entrance to the abbey is through a large inner court in the centre of which stands a Baroque Holy Trinity Column, designed by Giovanni Giuliani and completed in 1739.

The Baroness Mary Vetsera, party to a suicide pact in nearby Mayerling with Crown Prince Rudolf von Habsburg, is buried in the village cemetery near Heiligenkreuz.

Presently, over 90 monks belong to the monastic community, the focus of which is the liturgy and Gregorian chant in Latin (in the Ordinary Form of the Roman Rite).

Heiligenkreuz is also home to the Priesterseminar Leopoldinum (formerly Collegium Rudolphinum), a theological college for men in preparation for the priesthood.

[1] Stift Heiligenkreuz is known today as one of the most vibrant monasteries in central Europe; the current abbot is a member of the Ratzinger Schülerkreis; one of the monks is the Procurator General of the Order, working in Rome.

It was one of the first abbeys to realize the value of the internet apostolate, maintaining a frequently updated homepage and several groups on Facebook as well as various blogs such as The Monastic Channel, Sancrucensis, and EUCist News.