Millie is an English nickname for Millicent, Mildred, Camilla or Amelia that has become a name in its own right; Millicent comes from the Germanic Amalaswinth and means "strong worker", while Mildred means "gentle strength". It was a common name around 1900 and has returned with other cozy vintage nicknames such as Sadie and Hattie. Millie ranked number 2008 in the United States in 2000, entered the top 1000 in 2009, rose from number 469 in 2015 into the top 100 in 2024 and reached number 73 among girls in 2025.