Saint Adwen or Adwenna was a 5th-century Christian virgin and saint. She is recorded as a daughter of Brychan, king of Brycheiniog in south Wales, in the CornishLife of Saint Nectan and in Robert Hunt's collection of Cornish legends. These sources associate her with the establishment of the parish of Advent in Cornwall.
The saint's feast day is unknown. In Cornwall Adwen was traditionally the patron saint of sweethearts.