Millie is a moderately popular girls' name in United States, ranking #128 in 2022 with 2,195 recorded births. The name reached its all-time peak in 2024 with 2,910 births ranking #86. Since 1996, the popularity has increased by 6,355.9%. In 2022, approximately 1 in every 747 girls born was named Millie. RISING Recent data shows the name is currently rising.