Tissue regeneration relies on adult stem cells (SCs) that possess the ability to self-renew and produce differentiating progeny. In an analogous manner, the development of certain cancers depends on a subset of tumor cells, called cancer stem cells (CSCs), with SC-like properties. In addition to being responsible for tumorigenesis, CSCs exhibit elevated resistance to therapy and thus drive tumor relapse post-treatment. The epithelial-mesenchymal transition (EMT) programs promote SC and CSC stemness in many epithelial tissues. Here, we provide an overview of the mechanisms underlying the relationship between stemness and EMT programs, which may represent therapeutic vulnerabilities for the treatment of cancers.