The pattern of RIASEC interests and academic skills were assessed longitudinally from a large-scale national database at three time points: eight grade, 10th grade, and 12th grade. Validation and cross-validation samples of 1000 males and 1000 females in each set were used to test the pattern of these scores over time relative to mean changes, stability, crystallization, and interest-career choice congruence as well as how these patterns were moderated by gender. Results indicate that the pattern of interests was fairly stable in grades 8-12 for males and females. Interests were also found to become more crystallized over time; however interest-career choice congruence evidenced an inverted V pattern. With further examination, student interests became less people based and their career choices more people based in grade 12. The results support the importance of grade 12 as a time of focus for research and intervention, and for continuing investigation of gender differences in adolescent career and academic development.