Women's parties have a unique and important role to play in the representation of women and women's issues and interests. They are neither a new nor a rare phenomenon and have emerged in a variety of contexts across time and space. And yet we know relatively little about them. This article argues that women's parties matter and that the study of women's parties matters. We contend that women's parties constitute a discrete party family; while there is a diverse range of women's parties, they can be viewed as a coherent group with similar origins, ideology, and naming patterns. This article offers the first research framework for the comparative study of women's parties. Building our knowledge of women's parties, we argue, is important for those interested in gender and politics, particularly those concerned with the representation of women's issues and interests.