Both victims were taken to Townsville University Hospital after being treated by paramedics at the scene.
Emergency services were called to the school at about 12:40pm.
The school entered lockdown immediately, a Department of Education spokesman told the publication in a statement.
"Any situation that threatens the safety and wellbeing of students or others in the school community is treated extremely seriously, and dealt with as a matter of priority," he said.
"The Department has arranged for additional support services to be made available immediately for parents, students and staff.
"Ongoing counselling and support is available for all students and staff.
"The school and department will work closely with authorities as they investigate this incident."
A woman was seen sitting with a child outside the school, with paramedics assessing them for injury, the Bulletin reports.
Police said a 16-year-old girl has been arrested in relation to the incident.