In Canada, changing demographics and increased competition--as well as social values based on equity--have inspired efforts to increase the postsecondary education (PSE) participation rates of youths from under-represented/under-served groups. Despite its population having the highest level of educational attainment among those of OECD countries, Canada appears to have made little progress in terms of narrowing "access gaps" and improving student retention rates. Provincial governments increasingly are funding a variety of targeted initiatives intended to encourage colleges and universities to enroll more special population students. This has proven challenging, however, as many institutions have neither holistic retention programs nor well-developed planning for such students. Consequently, access and success have become important public issues in Canada. A recent survey (Smith and Gottheil 2008) found that the under-served student groups served by Canadian colleges and universities are diverse. The groups of greatest interest include Aboriginal/First Nations/Inuit, recent immigrant, Asian, northern Canadian, rural, first-generation, low-income, francophone, and black students as well as students with disabilities. Using the strategic enrollment management conceptual framework, the authors focus on four of these groups: (1) low-income; (2) first-generation; (3) Aboriginal; and (4) francophone students. They describe each group and review specific barriers to PSE access as well as factors contributing to attrition. Finally, they offer six "lessons learned" to guide education leaders as they explore ways to better meet the needs of special population students. (Contains 1 figure and 3 footnotes.)