The liturgical year, also known as the church year, consists of the cycle of liturgical seasons in Christian churches which determines when feast days, including celebrations of saints, are to be observed, and which portions of Scripture are to be read either in an annual cycle or in a cycle of several years. Distinct liturgical colours may appear in connection with different seasons of the liturgical year. The dates of the festivals vary somewhat between the different churches, though the sequence and logic is largely the same.

In both East and West, the dates of many feasts vary from year to year, usually in line with the variation in the date of Easter, with which most other moveable feasts are associated. The extent to which feasts and festivals are celebrated also varies between churches; in general, Protestant churches observe far fewer than Catholic and Orthodox, in particular with regard to feasts of the Virgin Mary and the other Saints.

The liturgical cycle divides the year into a series of seasons, each with their own mood, theological emphases, and modes of prayer, which can be signified by different ways of decorating churches, colors of Paraments and Vestments for clergy, scriptural readings, themes for preaching and even different traditions and practices often observed personally or in the home. In churches that follow the liturgical year, the scripture passages for each Sunday (and even each day of the year in some traditions) are specified by a list called a lectionary.