Also called the Pactum Calixtinum, the Concordat of Worms was an agreement between Pope Calixtus II and Holy Roman Emperor Henry V on September 23 1122 near Worms.

Following efforts by Lamberto Scannabecchi (later Pope Honorius II) and the Diet of Würzburg (1121) in 1122, Pope Calixtus II and Holy Roman Emperor Henry V agreed to end the Investiture Controversy. By the terms of the agreement, the emperor guaranteed bribe-free election of bishops and abbots and renounced the right to invest them with ring and crosier, the symbols of their spiritual power. The pope granted Henry the right, in Germany, to be present at elections and to invest those elected with their lay rights.

The Concordat was confirmed by the First Council of the Lateran in 1123.