The Kollegiatsstift St. Peter und Alexander is a Catholic church located in Aschaffenburg, Bavaria, Germany. It is the town's oldest church, established in the 10th century, dedicated to Saint Peter and Saint Alexander. The main building was built as a Roman basilica, while other phases were built in the early Gothic style. The current structure is a cruciform basilica, reflecting a variety of styles including a Romanesque nave from the 12th century and a 15th-century tower.
The church is also notable for its Renaissance painting Beweinung Christi by Matthias Grünewald and the 10th-century Triumphkreuz. The Stiftskirche is open to the public and serves as a Roman Catholic parish church. A museum in the former chapter house exhibits church treasures and other historical artifacts.
The associated collegiate church was classified historical monument of Bavaria. Situated on top of a hill, the church has good views of the city of Aschaffenburg. The architecture of the monastery reflects different periods, from pre-Romanesque to the seventeenth century, although most of the current buildings date back to the 12th and 13th centuries.