Eastern Catholic churches observe an exceptionally rich liturgical calendar centered on the Paschal cycle (Easter). The calendar includes the Twelve Great Feasts of the Byzantine Rite: the Nativity of Christ, Theophany (Epiphany/Baptism of Christ), the Presentation of Christ in the Temple, the Annunciation, Palm Sunday, the Ascension, Pentecost, the Transfiguration, the Dormition of the Theotokos, the Nativity of the Theotokos, the Exaltation of the Holy Cross, and the Entry of the Theotokos into the Temple.

Marian feasts are particularly prominent in Eastern Catholic worship. The calendar also includes numerous feasts of saints from both Eastern and Western traditions, daily commemoration of saints, and several fasting seasons (Great Lent, the Apostles' Fast, the Dormition Fast, and the Nativity Fast). Some Eastern Catholic churches use the Julian calendar, meaning their Christmas falls on January 7 (Gregorian) rather than December 25.