Kornmarktkirche, Gothic church in Mühlhausen, Germany.

Kornmarktkirche is a long, single-nave former Franciscan church on the Kornmarkt, begun in the mid-13th century. Its rectangular choir has three stepped windows, and the eastern five bays of the south wall carry buttresses and tracery windows rebuilt after 1348. The interior has a flat wooden ceiling; a painted ornamental frieze was reconstructed in 1975.

Franciscans settled in Mühlhausen in 1231 on a donated plot that already held a chapel used as an oratory. Construction of the church in its present dimensions began in the mid-13th century, incorporating remains of an earlier building still visible in the north wall of the nave. The choir was raised in 1307, and after an earthquake the eastern window bays of the south wall were rebuilt in altered form in 1348. A square chapel was added at the southwest corner of the choir in 1392, and the tower's octagonal upper storey followed after 1400, with its slate-covered cap dating from 1568.

The church was profaned in 1802 and has served as a museum since 1975, so no worship takes place here. Its permanent exhibition "Luthers ungeliebte Brüder" (since 2014) covered pre-Reformation theology and the Peasants' War, focusing on radical reformers such as Thomas Müntzer. The former monastery garden was laid out following the ideas of the medieval scholar Albertus Magnus.

The church closes the full length of the Kornmarkt on its south side, with three entrances facing the square; the middle one has a large window portal. The building is currently closed while the state exhibition is dismantled, so check before planning a visit. The former cloister garden, laid out after the ideas of Albertus Magnus, lies by the north side, where remains of the vaulted cloister walk are still visible.

The church was never finished as planned: the corner responds with slanted bases for a cross-ribbed vault that was never built, and the nave now has a flat wooden ceiling. A painted ornamental frieze below the ceiling line was reconstructed in 1975. The building also holds the hereditary burial of the Mühlhausen branch of the Lutteroth family.