Objective: There is limited empirical research investigating the relationship between well-being and academic achievement and existing studies are largely conducted using cross-sectional methodology constraining conclusions regarding causality. Method: This study conducted at a South Australian high school addresses this gap by longitudinally investigating well-being and 10 academic achievement. Separate hierarchical regressions were run for Semesters 1 and 2 measures of academic achievement using ill-being, well-being, and gender as predictors. Results: In each case, ill-being and gender made a significant contribution to the prediction of academic achievement on the first step of the hierarchical regression. However, when well-being was added in the second step, ill-being no longer made a significant contribution. Each well-being 15 subscale positively correlated with academic achievement with the strongest effect being for perseverance. Conclusion: Positive education may therefore offer educators an avenue for simultaneously improving the well-being of students and their academic achievement.