Millie \m(il)-lie\ as a girl's name is a variant of Amelia (Latin, Old German), Camilla (Latin), Kamilla (Latin), Melissa (Greek), Mildred (Old English) and Millicent (Old French), and the meaning of Millie is "industrious, striving; work; helper to the priest; bee; honey; gentle strength; brave strength".

The baby name Millie sounds like Milli, Millee, Mille, Mollie, Mallie, Mellie and Maillie. Other similar baby names are Aillie, Billie, Gillie, Jillie, Lillie, Tillie, Milzie and Willie.