Abstract   The task of studying the impact of social class on physical and mental health involves, among other things, the use of a conceptual toolbox that defines what social class is, establishes how to measure it, and sets criteria that help distinguish it from closely related concepts. One field that has recently witnessed a wealth of theoretical and conceptual research on social class is psychology, but geographers' and sociologists’ attitude of diffidence toward this “positivistic” discipline has prevented them from taking advantage of this body of scholarship. This paper aims to highlight some of the most important developments in the psychological study of social class and social mobility that speak to the long-standing concerns of health geographers and sociologists with how social position, perceptions, social comparisons, and class-based identities impact health and well-being.