Martin S. Hagger is a Distinguished Professor in the Department of Psychological Sciences at the University of California, Merced working in the area of health psychology. He is also a Professor of Behavior Change in the Faculty of Sport and Health Sciences, University of Jyväskylä, Finland, and an Adjunct Professor and Research Consultant at the Department of Applied Psychology at Griffith University, Australia. He is currently a Senior Co-Editor of the Health Psychology section of Social Science & Medicine. He received a Highly Cited Researcher Award from Clarivate Analytics four years in a row (2020-2023). His research applies social psychological theories to predict health behaviors and inform behavior change interventions. In particular, he studies relations between theory-based psychological constructs (e.g., attitudes, intentions and motives, self-efficacy, perceived control, self-control, habit, planning, and personality traits) and health-related behaviors and how health professionals can use knowledge of these relations to promote health behavior change through intervention.