Longitudinal studies suggest modest continuity in personality from adolescence to early adulthood and greater continuity over successive periods during the adult years. However, individual differences in personality stability do exist. We discuss potential sources of personality change, especially as they relate to development, role assumption and commitment, and loss of roles and commitments. Then, using data from the Intergenerational Studies, we employ measures of competence and of work and family commitments, assessed both in high school and adulthood, to predict personality stability from high school to early and late adulthood. Results indicate that personality stability can be successfully predicted with such measures. Greater personality stability is found for those determined to be more “planfully competent,” but additional family and work role variables also increase predictive power, in some instances. Using two alternate measures of competence—ne from the California Q-sort and the other from the California Psychological Inventory—we replicated the finding that men with more disorderly careers show less personality stability, and that women who have experienced more divorces show less personality stability.