Duncan is a moderately popular boys' name in England & Wales, ranking #493 in 2005 with 56 recorded births. The name reached its all-time peak in 1996 with 139 births ranking #220. Since 1996, the popularity has decreased by 59.7%. In 2005, approximately 1 in every 5,526 boys born was named Duncan. FALLING Recent data shows the name is currently falling.