Cassidy is a moderately popular girls' name in United States, ranking #478 in 2021 with 655 recorded births. The name reached its all-time peak in 1999 with 3,395 births ranking #99. Since 1996, the popularity has decreased by 77.0%. In 2021, approximately 1 in every 2,503 girls born was named Cassidy. STABLE Recent data shows the name is currently stable.