Concerns over equity of access to higher education are widespread, but there is significant disagreement over what should constitute a fair system. This article assesses diverse conceptualisations of equity and explores the ways in which they embody themselves in the policies of three systems, those of England, Brazil and Kenya. While showing significant disparities of income level and enrolment ratio, all three have made concerted efforts to expand higher education access, accompanied by increasing stratification in terms of the quality and prestige of institutions. Analysis of policy options and outcomes leads to a proposal of three principles for understanding equity of access: availability, accessibility and horizontality. The third of these principles addresses the little-acknowledged safeguard that disadvantaged students should not be confined to lower-quality institutions, while at the same time allowing for diversity of ethos and disciplinary focus.