To assess the developmental relationship of perceptions of self-concept and gender role identification with adolescents' attitudes and achievement in science, a two-year longitudinal study was conducted. A battery of instruments assessing 16 dimensions of self-concept/gender role identifications was employed to predict students' achievement and attitudes toward science. Specific behaviors studied included self-concept in school and science and mathematics, attitudes toward appropriate gender roles in science activities and careers, and self-perceptions of masculine and feminine traits. One hundred and fifty-five adolescents, enrolled, respectively, in the seventh and eighth grades, participated in the study. Through Fisher z transformations of correlation coefficients, differences in relationships between these two sets of variables were studied for males and females during the two years. Results indicated that students' self-concepts/gender role perceptions were related to both achievement and attitudes toward science, but more related to attitudes than achievement. These relationships became more pronounced for students as they matured from seventh to eighth graders.