This study tested and extended Dweck's social-cognitive theory of motivation with adults who deliberately chose to face the challenge of returning to school. We examined the relationships among beliefs (implicit theories) on the nature of intelligence, goal orientation, cognitive engagement in learning, and achievement using path analyses. Findings were generally consistent with Dweck's theoretical predictions. Striving for competence improvement (mastery goals) had a positive impact on learning activities and outcomes, while striving to demonstrate competence (performance goals) or to avoid effort (work avoidance) had a negative influence on learning and achievement. Additionally, data suggested that mastery goals had a positive influence on academic achievement through the mediation of effort expenditure. The predicted effects of implicit theories of intelligence on goal orientation and cognitive engagement in learning, however, failed to emerge. Results are discussed in relation to their general theoretical implications and with regard to the specific characteristics of returning to school adults.