Although it has been proposed that general mental ability (GMA) may affect the adjustment process, few studies have examined the relation of mental ability to individuals' sense of satisfaction with school and work. The present study investigated the importance of mental ability for school and job satisfaction, using a Swedish sample of 298 men and 399 women, followed longitudinally from the age of 13 to middle age (43 years for women, and 48 years for men). Mental ability had a weak positive correlation with school satisfaction at age 13 but not at age 16, whereas a tendency was found for a negative relation to job satisfaction at the age of 26. Adolescent levels of mental ability were associated with greater intrinsic job satisfaction in middle age for both sexes, and greater extrinsic job satisfaction for men. Longitudinal structural equation modeling indicated that the effects of general mental ability on school and job satisfaction were mediated by school and work achievement, respectively. The same model fit both sexes.