Many school-level policies, such as school funding formulae and teacher allocation mechanisms, aim at reducing the influence of students’ low socio-economic condition on academic achievement. Benchmarks and indicators based on large-scale international assessments can be used to measure academic success and identify if and when disadvantaged students are successful. We build on such work and develop a new method for identifying a cross-country comparable metric of the academic success of socio-economically disadvantaged students using data from the Programme for International Student Assessment (PISA). We estimate the prevalence of successful disadvantaged students in 56 countries, as well as changes over time between 2006 and 2015. In addition, we focus on the PISA 2015 edition and explore school factors associated with the probability that disadvantaged students will be successful academically in a subsample of 18 countries. Findings reveal that successful disadvantaged students attend schools with a better disciplinary climate and that provide additional time for instruction in key subjects.