Siobhan is a distinctive girls' name in United States, ranking #1579 in 1999 with 107 recorded births. The name reached its all-time peak in 1997 with 139 births ranking #1272. Since 1996, the popularity has decreased by 22.5%. In 1999, approximately 1 in every 16,577 girls born was named Siobhan. FALLING Recent data shows the name is currently falling.