While access to postsecondary education in Canada has increased over the past decade, a number of recent studies demonstrate that youth from disadvantaged socioeconomic backgrounds are vulnerable to some degree of exclusion from postsecondary education. These studies tend to emphasize the lack of financial resources and social capital as the main sources of this vulnerability. Our paper employs multilevel framework to explore the extent of the impact of schools on access to postsecondary education, especially for youth from disadvantaged background. Our analyses revealed that: (1) for youth with similar financial constraints who attend schools with relatively similar quality, those from disadvantaged socioeconomic backgrounds who attend schools with high concentration of low SES students are particularly vulnerable to exclusion from university education, and (2) a substantial portion of the SES effect operate through the impact of high school academic achievement and postsecondary education expectation on access to postsecondary education. (Contains 4 tables.)