Growth curve modelling was used to trace the trajectory of the prestige dimension of career aspirations from Grade 9 through to 3 years after high school, as a function of gender and early high school math achievement. The sample consisted of 218 university-bound adolescents (129 female, 89 male). Initial aspiration levels, the slope, and the curvature of the trajectories all differed significantly as a function of Grade 9 math performance. No significant gender or gender by achievement effects were found. These results support the notion that math achievement functions as a "critical filter" to subsequent career aspirations, with youth who performed poorly in Grade 9 math aspiring to careers that were of lower prestige. Implications of this research are discussed in terms of the development of young women's career aspirations, vocational outcomes, and involvement in higher level mathematics education. (Contains 1 figure and 4 tables.)