This chapter introduces social justice as a foundational principle in nursing, emphasizing its ethical, historical, and global dimensions. Drawing on professional frameworks such as the ANA Code of Ethics and ICN guidelines, it situates nursing as both a clinical and advocacy-based profession (American Nurses Association, Code of ethics for nurses with interpretive statements. American Nurses Association, 2015; International Council of Nurses. Code of ethics for nurses. International Council of Nurses. https://www.icn.ch/nursing-policy/icn-code-ethics , 2021). The chapter explores the relationship between social determinants of health and health inequities, highlighting persistent disparities across race, class, and geography (Braveman et al, What is health equity? And what difference does a definition make? Robert Wood Johnson Foundation, 2017). Historical contributions from pioneers such as Nightingale and Wald are examined to illustrate nursing’s longstanding role in social reform. The chapter concludes by framing social justice as inseparable from nursing identity and practice.