The O Antiphons, fervent prayers asking Our Lord to come to us, address Jesus by His Old Testament titles. They are sung before and after the Magnificat during Vespers, the evening prayer of the liturgical office. The Antiphons begin on December 17 and end on December 23.
| December 17 | O Sapientia | O Wisdom |
| December 18 | O Adonai | O Lord |
| December 19 | O Radix Jesse | O Root of Jesse |
| December 20 | O Clavis David | O Key of David |
| December 21 | O Oriens | O Dawn |
| December 22 | O Rex Gentium | O King of the Gentiles |
| December 23 | O Emmanuel | O Emmanuel |