Chemainus Secondary School was the scene of another fire in a little more than a week, and the latest one also started in a washroom.
Mike Russel of the Cowichan Valley School District says it was spotted just after 1 pm by a custodian.
Staff and students evacuated the building safely and firefighters quickly extinguished the fire.
The cause of the fire and extent of damage is unknown at this time.
Just over one week ago, on February 20, a fire started in a second-floor washroom at Chemainus Secondary School and fire investigators say it was suspicious.
The RCMP is continuing to investigate.
Chemainus Secondary School has about three-hundred-and-50 students.