This article examines how social determinants of health—such as housing, nutrition, education, and the built environment—shape health outcomes and life expectancy across and within countries. By exploring global data, community-level disparities, and real-world initiatives led by healthcare organizations, governments, and civil society, it highlights why improving health equity requires action far beyond the clinic. Ultimately, it underscores the need for cross-sector collaboration to address the root causes of health disparities and build healthier, more resilient communities.