Prisons across the globe are manifestations of inequality. In any society, its most marginalised groups are overrepresented in prisons and all institutions of criminal justice. Notwithstanding this universal condition of contemporary criminal justice, the link between social inequality and inequality of punishment has been found to be tenuous and elusive. This contribution addresses the question how socio-economic inequality shapes the manifestations of punishment for a global sample of countries. As socio-economic inequality and criminal punishment are both multi-faceted concepts, several indicators are used for each. The findings confirm the highly contextual nature of the link between inequality and criminal punishment; they suggest a variegated impact of political economies, and a multiplicity of mechanisms that link inequality and criminal punishment across the globe.