The Rat Wife in Little Eyolf is a significant and atypical female character in the development of late nineteenth century theatre. The complexity of this character offers costume designers numerous visual possibilities. This thesis uses conventional literary research, performance analysis, and a study of the creative design process to explore possible costuming approaches to the construction of the Rat Wife image. It traces the character s roots in folkloric, historical and biographical sources, and applies this knowledge to the creation of the Rat Wife s image. It argues that costume is an essential element in the defining of theatrical personae. One of the objectives of this study is to analyse and compare the costuming of the Rat Wife and show the diversity of approaches used by designers in multiple international productions. Finally, this thesis contains examples of my own costume designs for the Rat Wife; my aim is to show how practitioners can use scholarly theatre research during the creative process of costume design.