Duncan is a moderately popular boys' name in England & Wales, ranking #289 in 1997 with 93 recorded births. The name reached its all-time peak in 1996 with 139 births ranking #220. Since 1996, the popularity has decreased by 33.1%. In 1997, approximately 1 in every 3,381 boys born was named Duncan. FALLING Recent data shows the name is currently falling.