Some people will follow a different educational path despite having the intellectual ability to do well in school. This study explored how educational achievers and underachievers were different from each other in middle adulthood as well as examined which individual and contextual factors in adolescence were important to educational underachievement in middle adulthood. Participants are a school cohort followed from age 10 to middle adulthood (N = 1,326) and are from the Swedish longitudinal research program entitled Individual Development and Adaptation. This study focuses on a subgroup of Individual Development and Adaptation participants (n = 304) with above average intelligence (Mean IQ = 119.39, SD = 5.97). Study findings showed that a minority of adolescents in the study focal group (26%) did not complete high school, and women were more likely to educationally underachieve than men. A simultaneous multilevel logistic regression, with school class accounted for in the analysis, showed that for those of above average intelligence parents' socioeconomic status and school grades were the strongest predictors of educational attainment. Finally, in midlife, underachievers had lower incomes and occupational levels, drank less frequently, and rated their health as worse than achievers. Study implications are discussed in terms of ways to advance the field of gifted underachievement and in relation to Swedish gifted educational policy.