Siobhan is a moderately popular girls' name in England & Wales, ranking #310 in 2001 with 118 recorded births. The name reached its all-time peak in 1996 with 332 births ranking #138. Since 1996, the popularity has decreased by 64.5%. In 2001, approximately 1 in every 2,271 girls born was named Siobhan. STABLE Recent data shows the name is currently stable.