Canada depends on a steady flow of immigrants to maintain a viable workforce within an aging population. Without immigration, Canada's dependency ratio--the number of employed versus non-employed individuals--would grow dangerously unbalanced. In recent years, most immigrants have come from countries where the spoken language is not English or French and settled largely in Toronto, Montreal and Greater Vancouver. As a result, many urban schools are composed predominantly or significantly of students for whom the language of instruction is not one that they speak at home. Over 50% of the Toronto District School Board population has a mother tongue other than English; this figure is about 37% in Greater Vancouver districts; and about 34% in Montreal. Given the role of school as a major mediator of life opportunities and Canada's particular commitment to equality and multiculturalism, it is important to ensure that these English-as-a-second-language (ESL) students have the necessary support to succeed in Canadian schools. However, until recently, relatively little was known about the academic trajectories of these students. New research has revealed wide variations in outcomes among sub-groups of ESL students. Research recently undertaken in British Columbia has highlighted the need to look beneath labels like "ESL" and "immigrant students" to observe wide variation in the outcomes of students subsumed by these labels. Further studies underway in Vancouver, Toronto and Montreal appear to echo these findings. (Contains 6 figures.)