Girls continue to be underrepresented in Year 11 and 12 intermediate and advanced mathematics courses in Australia, which has implications for their future educational opportunities and career aspirations. The present study compared the choices of 84 Year 10 girls and boys from one school for their Year 11 mathematics course, with their teachers’ recommendations for the same. Findings indicated that while most participants made course selections aligned with their teachers’ recommendations, girls tended to under-aspire and boys tended to over-aspire in their choice decisions, based on their teachers’ recommended course choices. In addition, utilising the Expectancy-value theoretical (EVT) framework, we surveyed participants to measure their self-perceptions (self-concept), and values about mathematics (intrinsic value, utility value, and attainment value). We also measured participants’ views on the domain of mathematics (sense of belonging, growth mindset, the status of mathematics, gender bias). Multivariate analysis of variance indicated that girls showed lowered self-concept, sense of belonging, and growth mindset than boys, also viewing mathematics as less of a high-status subject than boys. In addition, the survey obtained participants’ opinions on sociocultural influences on their mathematics course selections, with no significant gender differences noted.