The workweek and weekend are those complementary parts of the week devoted to labour and rest respectively. The legal working week (British English), or workweek (U.S. English), is the part of the seven-day week devoted to labor. In most Western countries it is Monday to Friday. The weekend comprises the two traditionally non-working days in the seven-day week.

What constitutes the workweek is mandated either by law or custom. In Christian tradition, Sunday is the "Lord's Day" and the day of rest and worship. The Jewish Sabbath, known as Shabbat, lasts from sunset on Friday to the fall of full darkness on Saturday. The French Revolutionary Calendar had ten-day weeks and allowed decadi, one out of the ten days, as a leisure day.

The present-day concept of the weekend first arose from the Dies Solis (Day of the Sun) decreed by Constantine, and the Biblical Sabbath. The weekend in Western countries comprises Saturday and Sunday, when most employees do not have to work. Whereas the Sabbath itself was just one day each week, the preceding day also came to be taken as a holiday, because it was considered necessary to do preparatory tasks at home that would permit proper Sabbath observance the next day.[citation needed]