The Ethiopian Orthodox Tewahedo Church observes the most extensive liturgical calendar of any Christian church. The Ethiopian calendar (with 13 months and a year approximately 7–8 years behind the Gregorian calendar) organizes a year packed with feasts, fasts, and saints' commemorations. Christmas (Genna/Lidat) is celebrated on Tahsas 29 (January 7, Gregorian) and Theophany (Timkat) on Ter 11 (January 19, Gregorian). Timkat is the most spectacular celebration, involving a procession of the Tabot to a body of water where it is kept overnight, with thousands of white-robed faithful gathered.

Marian feasts number at least 33 per year. Major fasts include the Great Ethiopian Lent (Tsome Nibiyet, 55 days, the longest in Christendom), the Fast of the Apostles, the Fast of the Virgin (Tsome Filseta, 16 days in August), and Advent (Tsome Gena, 43 days). Ethiopian New Year (Enkutatash) falls on September 11 and is a major national and religious celebration. The Ethiopian Synaxarion (liturgical calendar of saints) includes an extraordinary number of uniquely Ethiopian saints: Tekle Haymanot, Lalibela, Yared, and many others. Both Saturday and Sunday are observed as holy days.