Siobhan is a moderately popular girls' name in England & Wales, ranking #228 in 2000 with 180 recorded births. The name reached its all-time peak in 1996 with 332 births ranking #138. Since 1996, the popularity has decreased by 45.8%. In 2000, approximately 1 in every 1,518 girls born was named Siobhan. STABLE Recent data shows the name is currently stable.