Fionna is a distinctive girls' name in United States, ranking #13769 in 2025 with 6 recorded births. The name reached its all-time peak in 2012 with 41 births ranking #3804. Since 1996, the popularity has decreased by 50.0%. In 2025, approximately 1 in every 267,878 girls born was named Fionna. FALLING Recent data shows the name is currently falling.