Millie is a highly popular girls' name in England & Wales, ranking #27 in 2021 with 1,472 recorded births. The name reached its all-time peak in 2004 with 2,421 births ranking #22. Since 1996, the popularity has increased by 354.3%. In 2021, approximately 1 in every 186 girls born was named Millie. FALLING Recent data shows the name is currently falling.