Motivated by chronic declines in post-compulsory high school science participation, this research provides a new perspective on the enrolment decisions of science proficient Year 10 students in New South Wales (NSW). The study adapted the 'multiple worlds' model of Phelan, Davidson and Cao (1991) to explore students' perceptions of their family, peer, school science and mass media worlds, for influences on their decisions about enrolling in post-compulsory science courses. A survey of 196 science proficient students, in six schools, provided a context for interviews with 37 students deciding for, or against, taking further science. The study considered influences within each world, and the effects of congruency or incongruency between cultural features of different worlds. The opinions of 24 science teachers regarding the enrolment decisions of science proficient students provided a triangulation of perspectives. The study found science proficient students often cross referenced perceptions of the attitudes and values within family and school science worlds when deciding whether to take science courses. In particular, the resources of cultural and social capital within students' families were strongly influential in many decisions, since experiences of school science alone did not tend to encourage further participation, particularly in the physical sciences. Teachers' opinions that science proficient students were being drawn away from science courses and careers by external influences were not supported by students' narratives