Previous research has documented substantial overqualification and an association with social disadvantage and fields of study. Overqualification persistence has been less studied. Persistence is more important than prevalence because skill and job matches are likely to involve lags. Our data set allows us to estimate the prevalence, the correlates, and the persistence of overqualification among Canadian postsecondary graduates using two different measures. We find: i) substantial overqualification and overqualification persistence; ii) the socially disadvantaged and those with less vocational diplomas were more likely to be overqualified but not more likely to move to a match; iii) mobility and academic performance seem to influence catch-up; iv) choice of overqualification measure has large effects on results.