Health psychology and behavioral medicine are interdisciplinary fields devoted to developing and integrating the biomedical, behavioral, psychological, and social sciences and approaches to better understand health and illness, and to applying these sciences and approaches to prevention, diagnosis, treatment, and rehabilitation. They have a wide range of research and clinical foci and applications across an array of health‐related behavior problems and goals across multiple contexts and settings. Behavioral and psychophysiological assessments and treatments, as well as multimethod, multimodal, and multisource assessments, are emphasized. Their conceptual and scientific foundation is based on the biopsychosocial model, behavior change theories, and personality constructs. Their historical and philosophical foundation predates psychology as a distinct discipline. Developing areas in the field include sociocultural applicability, translational research, health disparities, new and emerging technologies in providing health care, accessibility of health psychology to the public, and the public health needs of less developed countries.