Siobhan ranked #3506 among U.S. baby names in 2024. Since 1956, 7,310 babies have been named Siobhan, peaking in 1980 with 282 births. The 1980s were its biggest decade, with 2,086 births. Siobhan is on the rise, up about 95% over the past five years. It is predominantly a girls' name.