The Coptic Orthodox Church observes Sunday as the Lord's Day—the Day of the Resurrection—and the primary day of Eucharistic assembly. The Jewish Sabbath (Saturday) is not obligatorily observed as a rest day in the manner of the Old Testament commandment. However, Saturday retains liturgical significance in the Coptic calendar as a day of commemorating the departed and as a quieter day of prayer, and Vespers (evening prayer) on Saturday prepares for Sunday worship.

The Coptic Church uses the Coptic calendar—an ancient Egyptian liturgical calendar derived from the ancient Egyptian calendar—to calculate feast days. The Coptic year begins on September 11 (Gregorian) or September 12 in a Gregorian leap year. The Coptic calendar preserves pre-Christian Egyptian month names (e.g., Tout, Baba, Hatur) now filled with Christian content. This distinctive calendar means that Coptic feast dates sometimes differ from both the Western Gregorian and the Eastern Julian calendars.