Lewellyn is an uncommon name of Welsh origin, derived from the elements llwy meaning "leader" and elwyn meaning "friend". It is often associated with the Welsh prince Llywelyn ap Iorwerth, also known as Llywelyn the Great, who ruled Wales in the 12th century. The name Lewellyn has been used predominantly in Wales but can also be found in other parts of the world where there are Welsh communities or those with an interest in Welsh culture and history. It is a name that exudes strength and friendship, reflecting its components' meanings. Lewellyn was more common in the late 19th to early 20th centuries but has since become less prevalent, making it unique and distinctive today.
The name Lewellyn experienced varying popularity over these years, with peaks in the late 1920s and early 1940s, but generally remained uncommon throughout this period.