Defining, estimating, communicating about, and dealing with overdiagnosis is challenging. One reason for this is because overdiagnosis is a complex phenomenon. In this article we try to show that the complexity can be analysed and addressed in terms of three perspectives, i.e., that of the person, the professional, and the population. Individuals are informed about overdiagnosis based on population-based estimates. These estimates depend on professionals' conceptions and models of disease and diagnostic criteria. These conceptions in turn depend on individuals' experience of suffering, and on population level outcomes from diagnostics and treatment. As the personal, professional, and populational perspectives are not easy to reconcile, we must address them explicitly and facilitate interaction. Population-based estimates of overdiagnosis must be more directly informed by personal need for information. So must disease definitions and diagnostic criteria. Only then can individuals be appropriately informed about overdiagnosis.