This chapter explores American philosopher Iris Marion Young’s central contributions to contemporary political theory. Young remains well known as a leading socialist, feminist political theorist, whose ground-breaking work on oppression, equality, and democratic theory has had an enduring impact, despite her premature death. After introducing Young’s multifaceted engagements with issues of justice and equality against the backdrop of her personal and political contexts, the chapter examines her influential account of oppression. This analysis is essential to understanding Young’s conception of equality as inclusion. The chapter then analyses her critique of the universal model of citizenship as delineated in her celebrated 1990 book Justice and the Politics of Difference.