The category of life-threatening and/or chronically debilitating ‘rare disease’ has been afforded increasing importance within both national and global health policies over the past two decades. Although lacking a universal definition, it is estimated that between 263 and 446 million individuals are currently living with one of the five thousand to eight thousand diseases defined as rare, around 80% of which have a genetic basis; many are inherited and often emerge in childhood. Individually rare but collectively numerous, rare diseases affect the health of individuals and families and engage their kin, health professionals, public health authorities, and patient advocacy organizations. Building on ethnographic fieldwork in Europe and Asia, this chapter examines anthropological and social science research on rare diseases in the context of global health. The global connectedness of diseases, people, and institutions that characterizes global health is equally important for rare diseases. Focusing on praxis and lived experiences, anthropology can help counterbalance Western supremacy and biomedical reductionism in the global rare diseases field. This chapter emphasizes the overall scarcity of expertise, resources, and patient data across national levels and discusses newborn screening, migration, and ‘therapeutic remoteness’ as key issues at the intersection of rare diseases, medical anthropology, and global health.