This article examines the significance of Caroline Bond Day's vindicationist anthropological work on mixed-race families early in the 20th century. Day used the techniques of physical anthropology to demonstrate that mixed-race African Americans were in no way inherently deformed or inferior. Using Day's published work and unpublished correspondence, I show that her study was noteworthy for two reasons. First, unlike most other anthropologists of her time, but presaging later scholars, she studied her own family and social world, a perspective that both gave her unique data unavailable to others and removed barriers between herself and her subjects. Second, as a mixed-race African American woman, she found herself not only fighting preconceptions about the racial inferiority of African Americans but also serving as a liaison between her research subjects and mainstream, White-dominated physical anthropology. This article argues that Day's importance as a scholar lies not only in her argument against racial inferiority but also in the outsider-within status that allowed her to make her case within academic anthropology in the early 20th century.