Cassidy is a moderately popular girls' name in United States, ranking #368 in 2019 with 865 recorded births. The name reached its all-time peak in 1999 with 3,395 births ranking #99. Since 1996, the popularity has decreased by 69.6%. In 2019, approximately 1 in every 1,939 girls born was named Cassidy. STABLE Recent data shows the name is currently stable.