Abstract Epithelial appendages share a common developmental program that relies on extensive interactions between epithelia and adjacent mesenchyme. The transcription factor p63 has a critical role in epithelial appendage development in both vertebrates and non-vertebrates. Both mice and zebrafish lacking p63 expression fail to develop epithelial appendages and other structures that develop as a result of epithelial-mesenchymal interactions. Furthermore, dominantly inherited mutations in p63 are the cause of a subset of human ectodermal dysplasias, which are characterized by developmental abnormalities in epithelia and epithelial appendages. While the importance of p63 for epithelial appendage development is evident, the molecular mechanisms by which p63 functions are largely unknown. In this review, we will discuss the current knowledge of the developmental role of p63 and the implications for epithelial appendage development.