Population health is a field that studies the health outcomes of a certain set of individuals or groups. Over time, the field has evolved to explore and account for relational interactions: (a) between and among individuals, (b) between individuals and their contexts, and (c) between individuals and the accessible services they use. These different interactions shape the health of population groups. This chapter explores opportunities and challenges influencing and shaping the field of population health. Populations are faced with challenges and barriers to sustained health due to health disparities, health inequities, and historical societal constructs. Population health practitioners can address these challenges by examining social determinants of health and multi-policy factors and using evidence-based approaches and collaborative multi-sector initiatives.