Although adolescent girls and women enroll in more science courses in high school and college than their male counterparts, the gender difference is reversed in subsequent employment in science-related fields (Landivar, 2013; NCES, 2013). Traditional gender stereotype endorsement and causal attributions about science success were investigated as predictors of elective science course enrollment in high school students. Participants (N=275) reported science stereotype endorsement and ability attributions for science success during the 10th grade, and transcript data were collected after students’ completion of the 12th grade. The relationship between stereotype endorsement and ability attributions was marginally significant for girls. There was a significant gender by stereotype interaction, such that stereotype endorsement predicted ability attributions more strongly for boys than for girls. Ability attributions were related to course enrollment for both boys and girls. However, stereotype endorsement was not related to course enrollment. These results support the hypothesis that ability attributions play a role in students’ elective science course selection, and that stereotypes may play a role in maintaining gender disparities in the sciences, particularly through their impact on boys’ educational choices.