Monday derives from words meaning "moon day." In Judaism the Torah is read on Monday mornings. Special penitential prayers are also recited. In the Eastern Orthodox Church Mondays are the days in which angels are commemorated. In many eastern monasteries monks fast on Mondays since they strive to live an angelic life. In Islam Monday was the day Muhammad used to fast on because it was the day he was born.

Children born on Monday are said to be fair of face. in Thailand yellow is associated with Monday. In the Netherlands Monday is said to be the most popular day to commit suicide, call in sick, and surf the web.