Ectodermal dysplasias (EDs) are a group of human pathological conditions characterized by anomalies in organs derived from epithelial-mesenchymal interactions during development. Dlx3 and p63 act as part of the transcriptional regulatory pathways relevant in ectoderm derivatives, and autosomal mutations in either of these genes are associated with human EDs. However, the functional relationship between both proteins is unknown. Here,we demonstrate that Dlx3 is a downstream target of p63. Moreover, we show that transcription of Dlx3 is abrogated by mutations in the sterile α-motif (SAM) domain of p63 that are associated with ankyloblepharon-ectodermal dysplasia-clefting (AEC) dysplasias, but not by mutations found in ectrodactylyectodermal dysplasia-cleft lip/palate (EEC),Limb-mammary syndrome (LMS) and split hand-foot malformation (SHFM)dysplasias. Our results unravel aspects of the transcriptional cascade of events that contribute to ectoderm development and pathogenesis associated with p63 mutations.