In the Catholic Church, Holy Days of Obligation are the days on which the faithful are obliged to participate in the Mass. They have also abstain from unnecessary works, "which hinder the worship to be rendered to God, the joy proper to the Lord’s day, or the suitable relaxation of mind and body." (Canon 1247 of the Code of Canon Law).

The list of Days of Obligation includes all Sundays in all countries. Some feasts, e.g. Easter, are always celebrated on Sundays, so they are always obligatory. The number of additional Days of Obligation varies between countries, from 1 in Hong-Kong to 10 in Vatican.

Holy Days of Obligation in 2022

Saturday, January 1 - Solemnity of Mary, Mother of God
Thursday, May 26 - Ascension of Jesus
Monday, August 15 - Assumption of the Blessed Virgin Mary
Tuesday, November 1 - All Saints Day
Thursday, December 8, The Immaculate Conception of the Blessed Virgin Mary
Sunday, December 25 - Christmas