Palais Harrach, Baroque palace in Landstraße, Vienna, Austria.

Palais Harrach was a garden palace on Ungargasse in Vienna's Landstraße district, built from 1727 to 1735 by Johann Lucas von Hildebrandt for Aloys Thomas Raimund von Harrach. It had two courts of honour and a chapel dedicated to Saint Januarius, whose altarpiece was painted by Martino Altomonte. The palace was demolished in 1968; only the chapel and a corner building on Juchgasse remain, beside the Schulzentrum Ungargasse built in 1985–1987.

Ernestine von Dietrichstein, widow of Count Gallas, bought a country house with garden in 1727 and enlarged it with neighbouring plots. Her husband Aloys Thomas Raimund von Harrach had Johann Lucas von Hildebrandt build the garden palace between 1727 and 1735, with two courts of honour and a chapel dedicated to Saint Januarius. In 1742 the estate passed to their son Friedrich August, governor of the Austrian Netherlands; his descendants sold it to Emperor Leopold II in 1791.

The palace chapel was consecrated to Saint Januarius, and Martino Altomonte painted its high altarpiece, the Apotheosis of Saint Januarius. The chapel survived the 1968 demolition of the ruined palace and was restored in 1985–1987, so it is the one part of the Harrach complex a visitor can still see, now within the Schulzentrum Ungargasse.

The palace itself no longer stands: its ruins were cleared in 1968, leaving only the Januarius Chapel and a corner building at Juchgasse. The chapel was restored in 1985–1987, when the Schulzentrum Ungargasse was built on the grounds between Ungargasse, Juchgasse, Boerhaavegasse and Barmherzigengasse. Look for the chapel within the school complex; the former riding hall opposite, built in 1850, survives in part as a hotel front.

The palace no longer stands: its ruins were demolished in 1968 after World War II bombing, leaving only the St. Januarius chapel and a corner building on Juchgasse. The chapel was restored in 1985–1987, when the Schulzentrum Ungargasse was built on the grounds.