This article presents the basic elements for developing a theory of the health transition. Such elements include the definition of concepts, the specification of a framework on the determinants of health status, the analysis of the mechanisms through which changes in health occur in populations, the characterization of the attributes that allow us to identify different transition models, and the enumeration of the possible consequences of the transition. The propositions are presented with a sufficient level of generality as to make them applicable to different contexts; at the same time, an attempt is made to provide them with the necessary specificity to account for different national experiences, thus opening a space for future comparative research efforts. Through the systematization exercise presented in this paper, we hope to contribute to the progress of a topic that has gained growing importance during recent years. Such importance is due to the enormous potential that health transition theory has for understanding and transforming the growing complexity of our times.