The dramatic increase in retention to Year 12, from 35 per cent in 1980 to 73 per cent in 2001, has had important effects on post-compuslory education provision in Australia. The changing student population and purposes of senior secondary education have led not only to diversity in curriculum and pedagogy within existing secondary schools, but also to diversity in institutional arrangments. This paper discusses prospects and problems of the relationship between senior secondary education and other educational sectors, which traditionally have functioned seperately. In recent years, senior secondary education has been re-aligned, in some instances, with further education rather than with junior secondary education. Experienced most clearly in multi-sector campuses and through inter-sectoral arrangements, the increasing diversity of educational provision for young people is redifining post-compulsory education, with the potential to enrich learning cultures in Australia.