Research conducted in England over the last decade has documented sustained, significant decreases in children’s wellbeing. While recent changes to curriculum policy promoting children’s wellbeing have been introduced, a notable feature of the discourse surrounding the promotion of children’s wellbeing is that wellbeing is regarded as opposed to, or in tension with, children’s academic achievement. Recently, Gabriel Heller-Sahlgren proposed that there is an inevitable ‘trade-off’ between children’s ‘wellbeing’ and their academic achievement. Using PISA 2012 data, Heller-Sahlgren argues that pupil happiness and high achievement do not go hand in hand; implying policymakers have a decision to make about which they uphold as the priority. In this article, I discuss the theoretical assumptions underpinning transnational comparisons of children’s wellbeing and review evidence from psychology and education to ascertain whether a trade-off is empirically supported. I argue that far from being incompatible, children’s wellbeing and achievement are positively associated. However, this relationship is not straightforward and requires careful disentangling of the hedonic and eudaimonic components of wellbeing. I underline four main gaps in current knowledge of the wellbeing-achievement relationship to date: the need for (1) multidimensional conceptualisation and measurement of wellbeing, (2) exploration of mediating mechanisms/constructs explaining the wellbeing-achievement relationship, (3) objective operationalisation of achievement, and (4) investigation of developmental differences. To conclude, I argue that when making policy recommendations researchers should avoid ‘all or nothing’ thinking which lures governments into false dichotomies.