Data were collected from female junior high school students (N=94) to identify the determinants of their intentions to enroll in at least one elective physical science course (e.g., physical science, chemistry physics) in high school. The model used in the study was Fishbein and Ajzen's Theory of Reasoned Action. According to the model it is supposed that the intention to perform a certain behavior is a function of the weighted attitude toward performing the behavior and the weighted subjective norm. The effects of external variables (e.g., science grades, academic ability) on females' intentions to enroll in at least one elective physical science course in high school are mediated by the model's theoretical constructs. The findings provide support for several hypotheses derived from the model. The females' intentions to enroll in at least one elective physical science course in high school were found to be a function of both attitude toward performing the behavior and subjective norm. Attitude toward performing the behavior and subjective norm, in combination, were found to predict behavioral intention with a high degree of accuracy. Attitude toward performing the behavior was also found to carry more weight than subjective norm in the multiple regression on behavioral intention. In contrast, academic ability, science grades, and attitude toward science failed to predict behavioral intentions, just as they were unrelated to the females' attitudes toward performing the behavior and subjective norms.