Siobhan is a moderately popular girls' name in England & Wales, ranking #313 in 2002 with 115 recorded births. The name reached its all-time peak in 1996 with 332 births ranking #138. Since 1996, the popularity has decreased by 65.4%. In 2002, approximately 1 in every 2,325 girls born was named Siobhan. STABLE Recent data shows the name is currently stable.