Two possible explanations of the relationship between expectancy and subsequent academic achievement were formulated and tested. The assumption that goal setting, by influencing actual and intended effort expenditure, might also determine both expectancy and subsequent performance, and thereby explain the relationship between the latter two variables, found little support. The hypothesis that expectancy determines how hard people work and thereby how well they perform found support only in a male group. Moreover, when previous academic achievement, goal setting, and effort expenditure were all controlled, expectancy was still found to relate to subsequent grades for both women and men. It was concluded that neither goal theory nor effort calculation theory could fully account for the relationship between expectancy and academic achievement.