All Souls' Day, also known as the Commemoration of All the Faithful Departed and the Day of the Dead, is a day of prayer and remembrance for the faithful departed, which is observed by Roman Catholics and other Christian denominations annually on 2 November. All Souls' Day is often celebrated in Western Christianity; Saturday of Souls is a related tradition more frequently observed in Eastern Christianity. Adherents of All Souls' Day traditions often remember deceased friends and relatives in various ways on the day. Through prayer, intercessions, alms and visits to cemeteries, people commemorate the poor souls in purgatory and gain them indulgences. Beliefs and practices associated with All Souls' Day vary widely among Christian denominations.

The annual celebration is the last day of Allhallowtide, after All Saints' Day (1 November) and Halloween (October 31). Prior to the standardization of Catholic observance on 2 November by St. Odilo of Cluny during the 10th century, many Catholic congregations celebrated All Souls Day on various dates during the Easter season as it is still observed in some Eastern Orthodox Churches and associated Eastern Catholic and Eastern Lutheran churches. Churches of the East Syriac Rite (Syro-Malabar Catholic Church, Chaldean Catholic Church, Assyrian Church of the East, Ancient Church of the East) commemorate all the faithful departed on the Friday before Lent.