Mark Siedner, MD MPH, is a practicing infectious disease clinician at Massachusetts General Hospital and an Associate Professor of Medicine at Harvard Medical School. His collaborative research program focuses on elucidating the determinants of health for people living with HIV in low and middle-income countries, and evaluating interventions to improve healthcare delivery for this population. Examples include a population-based longitudinal cohort study in South Africa to determine the consequences of intersecting HIV and non-communicable disease epidemics, and implementation science clinical trials to assess novel diagnostics and use of community health workers to improve healthcare delivery in rural Uganda and South Africa. He also dedicates substantial time to global health research capacity building as co-director of two research training grants, mentored support of dozens of scientific trainees on both sides of the Atlantic, and recognition with the Harvard Medical School Young Mentor Award.