Whitsun (also Whitsunday or Whit Sunday) is the name used in Britain, and other countries among Anglicans and Methodists, for the Christian holy day of Pentecost. It falls on the seventh Sunday after Easter and commemorates the descent of the Holy Spirit upon Christ's disciples (as described in Acts 2). In England it took on some characteristics of Beltane, which originated from the pagan celebration of Summer's Day, the beginning of the summer half-year, in Europe. Whitsuntide, the week following Whitsunday, was one of three holiday weeks for the medieval villein; on most manors he was free from service on the lord's demesne this week, which marked a pause in the agricultural year. Whit Monday, the day after Whitsun, remained a holiday in Britain until 1971 when, with effect from 1972, it was replaced with the Spring Bank Holiday on the last Monday in May. Whit was the occasion for varied forms of celebration.

In the North West of England, church and chapel parades called whit walks still take place at this time (sometimes on Whit Friday, the Friday after Whitsun). Typically, the parades include brass bands and choirs; girls attending are dressed in white. Traditionally, Whit fairs (sometimes called Whitsun ales) took place. Other customs, such as Morris dancing, were associated with Whitsun, although in most cases they have been transferred to the Spring bank holiday. Whaddon, Cambridgeshire has its own Whitsun tradition of singing a unique song around the village before and on Whit Sunday itself.