Ordinary time is the longest liturgical season in the Catholic Church, encompassing either 33 or 34 weeks each year. Because other liturgical seasons begin or end with movable feasts, the length of Ordinary time can vary slightly; however, 33 weeks is the more common length. The weeks are numbered, e.g., the first Sunday of Ordinary Time, the second Sunday of Ordinary Time, and so on.

Ordinary time is technically one liturgical season, though it is divided into two periods. Prior to the Second Vatican Council, when the term “Ordinary Time” was formally established, the two time periods were merely referred to as “the Season after Epiphany” and “the Season after Pentecost.”