In 2025, 3,353 US girls were named Millie, making it the 73rd most common girls’ name of the year, up 14 places from #87 in 2024. That is 433 more than the 2,920 girls named Millie in 2024. Its best rank for girls was #73, reached in this year, 2025. That year also had the most girls given the name: 3,353. For comparison, it was #469 in 2015 and #624 in 1950.
Social Security card records list Millie in every one of the 146 years from 1880 to 2025; in 1880 there were 105 babies with the name. In all, 46,138 US babies have been given the name, 99.5% of them girls and 0.5% boys. Its busiest decade was the 2020s, with 14,240 babies named Millie.
Over the 10 years from 2016 to 2025, 18,288 US girls were named Millie; the busiest of those years was 2025, with 3,353. In 2025 that was about 1 in 479 of the girls in SSA’s list for the year.
Among the states, Millie ranked highest in Utah in 2025, at #14 for girls there. It was in the top 100 in 34 states (counting DC). Related spellings in the SSA files include Mildred (452,998 babies since 1880), Millicent (11,825 babies since 1880), Milly (3,347 babies since 1880) and Mylie (1,982 babies since 1880). Rarer spellings such as Mellie, Mili and Milee are summarised on this page.