| Type: | Archbishop |
| Arnold of Selenhofen | |
| Archbishop of Mainz | |
| Church: | Catholic Church |
| Diocese: | Electorate of Mainz |
| Term: | 1153–1160 |
| Birth Date: | c. 1095/1100 |
| Death Date: | 24 June 1160 |
Arnold of Selenhofen (c. 1095/1100 – 24 June 1160) was the archbishop of Mainz from 1153 to his assassination in the Benedictine abbey St. Jakob, where he took shelter from the raging crowd.
He was born to a wealthy Mainz family. He studied at the University of Paris and became the treasurer of the archdiocese of Mainz, then provost of the cathedral. Conrad III made him archchancellor of Germany in 1151 and Frederick Barbarossa made him archbishop in 1153.
His administration of justice was unforgiving. While he was away in Italy working for the recognition of the Antipope Victor IV in 1159, the leading citizens rebelled. When he returned, he was murdered in front of the monastery of St. Jakob. He was buried in the church of St. Maria ad gradus (St. Mary of the Steps).