There is no single source of student records in Toronto, and many records have not survived. Check city directories for the period in which you’re searching for a list of schools that existed at the time. For much of Toronto’s history, its schools fall into the following three categories:
1) Public (government funded) primary and secondary schools
The Toronto District School Board maintains an archives that might be helpful. At present the collection is moving to a new location and is unavailable. We hope to add contact information soon.
2) Roman Catholic or “Separate” primary and secondary schools
There is a brief history that may help you narrow the search on the Toronto Catholic District School Board’s web site. You’ll also find contact information there.
3) Independent or Private schools (requiring fees)
Many of these schools are still operating and maintain archives. Use Google to search for their web sites and find out about availability of student records.
The Archives of Ontario holds records of standardized examination results for students in public schools, and other records of schools and teachers.
Many schools published histories and other commemorative volumes in conjunction with reunions and anniversaries. The Toronto Public Library is a good source. You can browse the catalogue using the name of the school or the keywords “Toronto” and “schools”.
Another growing source of information about Toronto’s schools is the Toronto Branch OGS project For King and Country. The project’s aim is to transcribe the war memorials in Toronto schools, but each school added to the site has a brief history and links to published histories.