Participation in advanced levels of mathematics in secondary school is ofinterest to those involved in educational policy and practice as well as those involved in research. This paper uses multilevel analyses (including a trichotomous outcome variable) of longitudinal data from a nationally representative sample of Australian schools to investigate the influence of a number of factors on participation in mathematics (advanced, general, or none) in the final year of secondary school. The results suggest that the major influences on mathematics participation are gender and prior mathematics achievement. Both influences are substantial and independent of each other. Building a strong foundation in mathematics is likely to be an effective way of enhancing participation in advanced mathematics in the final year of school. However, although that may result in higher overall levels of participation in advanced mathematics, it is unlikely to alter the balance between boys and girls. Nor is the wider use of single sex schooling.