This study attempted to address limitations in the understanding of optimism and pessimism among middle-aged adults. Specifically, a model of affectivity as a mediator of the link between outcome expectancies and psychological adjustment (life satisfaction and depressive symptoms) was presented and examined in a sample of 237 middle-aged adults. Consistent with a mediation model, results of path analyses indicated that optimism and pessimism (particularly the former) had significant direct and indirect links (by means of positive and negative affectivity) with depressive symptoms and life satisfaction. These results add to the small but growing literature identifying optimism and pessimism as important concomitants of psychological adjustment in more mature adults.