Mildred McMillen (1884–1940) was an American printmaker.

McMillen was a native of Chicago who studied at the School of the Art Institute in that city^[1] from 1906 until 1913. There, she and her long-time companion Ada Gilmore first met.^[2] She and Gilmore spent time in France, studying with Ethel Mars and later at the Académie Colarossi, before the outbreak of World War I drove them back to the United States.^[3] Another teacher was Charles Hawthorne.^[4]

In 1914 McMillen and Gilmore settled in Provincetown, Massachusetts, where they became founding members of the Provincetown Printers.^[1] Notably, her prints are large in scale and black and white, unusual for members of the group.^[5] Several works by McMillen are owned by the Smithsonian American Art Museum,^[6] and she is represented as well in the collection of the National Gallery of Canada.^[7]