The ‘achievement gap’ – the term typically used to refer to differences in pupil attainment associated with social class, ethnicity and gender – remains an enduring obstacle to government goals of creating a socially just society. This article explores the nature of the achievement gap and some of the mechanisms that serve to perpetuate disadvantage in education systems providing a context in which to consider the appropriateness of government policies aimed at addressing the gap. Accessing predominantly English research but also consulting studies conducted in other education systems including the US and elsewhere in the UK, we argue that in contrast to its noble rhetoric, government approaches to addressing the achievement gap are preoccupied with standardised assessment and accountability (such as the latest attempt at raising pupil standards in England, the introduction of Academies) while paying little more than lip service to the persistent, underlying roots of inequality.