The principal can exclude you from a school if he or she believes that you have a serious contagious disease, or that your presence at the school would be detrimental to the physical or mental well-being of other students. This is a “refuse to admit”. You can appeal this decision to the school board.
If you are excluded by a principal from a school, you can still attend another school within the board.
Will my Ontario Student Record (OSR) impact going to post-secondary school?
In general, Canadian universities and colleges do not ask or receive copies of your OSRs when you apply for entry.
In other jurisdictions, eg. United States or UK, you should speak to the institution that you are interested in attending, or a lawyer in that jurisdiction to find out about their processes.
For information about how Ontario Student Records (OSRs) are managed and kept, visit the Government of Ontario’s Student Record Guidelines page.