Saint Justinus' church, Carolingian church in Höchst, Germany

Saint Justinus' church stands on the eastern edge of Höchst old town and displays a three-nave basilica with Gothic features and ornate Corinthian capitals. The structure overlooks the Main River valley, merging architectural styles from different periods.

Archbishop Otgar of Mainz had the church built around 830 after bringing relics of Saint Justin the Confessor from Italy; his successor Rabanus Maurus consecrated it around 850. In 1298 the relics were moved to St. Alban's Abbey in Mainz and the church was rededicated to Saint Margaret. From 1441 the Antonite order added the late Gothic chancel, and the monastery was dissolved in 1802.

The church was long called Margaretenkirche after St Margaret, to whom it was rededicated in 1298 when the Justin relics went to St Alban's Abbey in Mainz; the Höchst parish priest Emil Siering (1841–1899) pushed the original name back into use. The medieval church fair, the Margaretenkerb, kept the old name until 1961. Since 2009 the building has served as a summer church and wedding venue, and the Höchster Orgelsommer concert series uses its 1988 organ.

The church stands at the east end of Höchst old town above the Main, with a forecourt toward the town and a large flower and herb garden toward the river, bounded by the surviving Höchst town wall. The garden, planted in the early 1990s with medicinal herbs used by the Antonites, has been open to the public from spring to autumn since 2004. Since 2009 the church has served as a summer church.

Next to the church stands a medicinal herb garden where plants are grown following medieval cultivation methods. The garden is bordered by preserved sections of the old Höchst city wall, revealing the historical fortifications of the area.