Using a holistic conceptualization of teacher well-being in concert with the Job Demands and Resources (JD-R) framework, our interdisciplinary study examined associations among various job demands and resources and whole teacher well-being (i.e., professional, psychological, and physical well-being) in early care and education settings. First, we investigated direct associations of job demands and resources with teachers’ professional well-being. Second, we tested two models of potential mediation for the relationship of job demands and resources to well-being using structural equation modeling techniques: (a) that psychological and physical well-being mediate the relationship between demands, resources, and professional well-being; and (b) that professional well-being mediates the relationship between demands, resources, and psychological and physical well-being. Although our sample of early childhood teachers (n = 262) reported high levels of professional well-being (i.e., work commitment, self-efficacy), a substantial number of them experienced challenges in both psychological (e.g., perceived stress, depressive symptoms) and physical (e.g., ergonomic pain) well-being. As expected, teachers’ work-related stressors and work resources (positive work climate, quality of the physical environment) were directly associated with teachers’ professional well-being. Contrary to our expectations, however, instrumental resources (i.e, wages, health insurance) did not predict any aspects of teachers’ professional well-being. Our data only supported the first of the two tested mediation hypotheses (i.e., that psychological and physical well-being mediated the associations between working conditions and professional well-being), but with one caveat: physical well-being preceded psychological well-being in mediating the associations. These results advance our understanding of the challenges present in the early childhood workforce and have implications for policies and programs to improve teacher working conditions and well-being. (author abstract)