Human physiological systems are products of natural selection, evolved to develop and function in whole organisms that are integral components of surrounding social and physical environments. Developmental plasticity and ecological sensitivity are defining characteristics of human biology, and, as a result, global environmental variation produces substantial variation in human biology around the world. Yet the vast majority of research on human biology is conducted in controlled clinical settings in affluent industrialized countries, and cannot capture the full range of socio-ecological environments that may be important for gaining insights into the development, function, and evolution of critical physiological systems. A field-based, comparative approach to research on human biology in diverse communities around the world has the potential to advance our understanding of the causes and consequences of human biological variation, and to complement—and at times challenge—prevailing clinic- and lab-based research paradigms. This symposium features recent research in biological anthropology that highlights the value of a comparative human biology approach. Presentations will draw on data collected from field sites in North and South America, Asia, the South Pacific, and Africa to generate insights into human immune function, reproductive aging, nutrition and metabolism, and chronic disease.