Siobhan is a moderately popular girls' name in England & Wales, ranking #187 in 1998 with 229 recorded births. The name reached its all-time peak in 1996 with 332 births ranking #138. Since 1996, the popularity has decreased by 31.0%. In 1998, approximately 1 in every 1,263 girls born was named Siobhan. STABLE Recent data shows the name is currently stable.