The regulations will take effect Jan. 1 of next year, and licensed retirement homes and the majority of private care facilities will have up to five years to make the upgrades.
Other facilities, including public long-term care homes, are being given up to 11 years to complete the work.
Currently, only new facilities are required to have sprinklers.
The new regulations will also include more fire inspections and additional fire safety training for residence staff.
Ontario Fire Marshal Ted Wieclawek called the changes a "significant milestone" that will help protect the lives of seniors and firefighters.