Equity is a fundamental value and guiding principle of education policy and practice, but it is not necessarily actualised in schools and education systems around the world. There are large variations across PISA-participating countries and economies in the magnitude of the difference that socio-economic status makes in students' learning, well-being and post-secondary educational attainment. This suggests that policy and practice have a key role to play in reducing socio-economic inequalities in education. Equity does not mean that all students obtain equal education outcomes, but rather that differences in students' outcomes are unrelated to their background or to economic and social circumstances over which the students have no control. Equity in education means that students of different socio-economic status achieve similar levels of academic performance, and of social and emotional well-being, and that they are equally likely to earn desirable post-secondary education credentials, such as university degrees, that will make it easier for them to succeed in the labour market and realise their goals as adult members of society. Education systems need to determine how individual students learn best and tailor learning opportunities to meet their needs. The newly released PISA report, "Equity in Education: Breaking Down Barriers to Social Mobility," shows that narrowing the differences related to socio-economic status in what students near the end of compulsory schooling can do with what they have learned could offer more opportunities for children and young people born into disadvantaged families to move up the socio-economic ladder.