Significant declines in STEM ability beliefs and interest are often found during the transitions to middle school and high school. Girls generally report lower self-concept and interest in STEM compared to boys. Some children remain interested in math and science over these transitions, but we know little about the school and social factors that contribute to their continued interest and if these factors differ by gender. This study examines changes in math and science self-efficacy and interest over two school transitions and the final two years in high school. It further examines if changes and gender discrepancies in math and science interest, can be accounted for by self-efficacy, classroom qualities and the gender stereotypical beliefs about the usefulness of math and science.& Student in grades 5, 8, and 11 (N= 595) completed surveys on their math and science interest, self-efficacy, stereotypes, and classroom quality prior to transitioning to the next grade, and then one year post-transition. Although there were declines in interest and efficacy over school transitions they were not as substantial or pervasive compared to previous research. Gender differences were more apparent in high school than in earlier grades. Regressions analyses indicated that changes in interest over time were explained by self-efficacy, classroom quality, and gender stereotype beliefs, although gender stereotypes were only predictive of science interest.