Gwilym is a distinctive Welsh masculine given name, derived from the Old Norse elements 'Guð' meaning 'god' and 'hylmr' signifying 'helmet'. It has been used in Wales since medieval times, with historical figures like Gwilym ap Tudur, an ancestor of Henry VII, bearing this name. In English translations, it is often rendered as Guy or Gilbert.
The name Gwilym saw exactly five newborns in the year 2005.