This chapter discusses concepts of inequality and inequity in relation to health both within and between nations. It explores inequalities in health by characteristics, such as social class, gender, ethnicity, and the intersection of these. The chapter discusses the importance of the social gradient of health. It addresses competing explanations for health and social inequalities globally, including poverty and material deprivation, psychosocial factors, discrimination, and structural determinants of health. The ‘social gradient in health’ expresses the idea that health status is often patterned and that each successive increment in social position confers additional advantage. The way in which inequalities are measured, and the ethical pri...