One of the leading reasons behind social inequities is that elite groups have had access to more widespread and higher-quality educational opportunities much earlier, often when their economic returns were much higher. Nevertheless, measures of educational inequalities tend to focus exclusively on current differences within the school-age population. This paper proposes a new measure – the education inequity index (EII) – that captures cumulative differences in access to the economic returns of education across different groups. Concretely, the EII is the share of the cumulative wage premium appropriated by the elite over time in excess to that accrued by other groups. The paper advances a methodology to compute different versions of the EII using national household survey data. We then illustrate its applications by computing the economic, racial and gender EII for Brazil since 1980, separately for primary, secondary and college education. We showcase the new insights that the EII brings relative to other measures when it comes to monitoring inequities and informing policies to address them.