Health equity is both a moral imperative and a foundational pillar for achieving the Sustainable Development Goals (SDGs), particularly SDG 3, which aims to ensure healthy lives and promote well-being for all at all ages. Despite global commitments, vast inequities persist in access to healthcare, quality of services, and health outcomes across and within countries. These disparities are rooted in social, economic, political, and environmental determinants that disproportionately impact marginalized and vulnerable populations. This chapter explores health equity as a transformative pathway to sustainable development, analyzing its intersections with poverty, gender, education, climate change, and structural inequalities. By critically examining global health systems, we identify systemic barriers that hinder equitable access to care, such as inadequate financing, geographic inaccessibility, sociocultural exclusion, and fragmented governance. We present case studies from diverse contexts, highlighting successful models and community-led innovations that have advanced health equity. The chapter also emphasizes the role of universal health coverage, digital health tools, disaggregated data systems, and cross-sectoral policy integration in closing equity gaps. Furthermore, the chapter proposes a strategic framework for integrating equity into national and global health agendas, advocating for stronger political will, participatory governance, and inclusive health metrics. Bridging gaps in global health systems is not only critical for the realization of health-related SDGs but also essential for building resilient, inclusive, and just societies. As the world moves toward a post-pandemic recovery, placing equity at the center of health policies is vital for a sustainable and healthier future for all.