We study the relationship between locus of control and both educational attainment and college aspirations in adolescence, focusing on the potential channels through which locus of control may influence these outcomes. Even after controlling for a comprehensive set of socio-demographic factors and cognitive skills, there remains a strong correlation between locus of control, college aspirations, and attendance. We show that effort is an essential channel through which locus of control operates. Mediation analysis further reveals that this mechanism is more influential than future expectations in determining high-school graduation, college aspirations, and attendance.