This study investigates the incidence of over-education amongst recent Australian bachelor degree graduates and its effect on their earnings. We find that between 24% and 37% of graduates were over-educated shortly after course completion, with over-education most common amongst young females and least common amongst older females. Over-education rates vary markedly across major fields of study and appear to be associated with the relative demand for graduate labour. Overeducation was less common three years after course completion; however a nontrivial proportion of graduates remain over-educated. With regard to the effect of over-education on earnings, we find a notable age-related effect not reported in earlier studies. Young over-educated graduates were not penalised after unobserved heterogeneity had been addressed, whereas older over-educated graduates were at an earnings disadvantage relative to their well-matched peers. (Contains 6 tables.)