A child was killed in a collision between two sedans on Highway 89 east of County Road 25 in Melancthon Township, near Shelburne.
First responders responded to the scene shortly after 5:30 p.m. on Friday.
Dufferin County OPP says a seven-year-old girl was airlifted to a trauma centre where she died of her injuries.
The driver of that vehicle and the driver and passenger of the other car was transported to the hospital with non-life-threatening injuries.
Police are looking into the cause of the collision. Anyone who may have witnessed the collision or has dashcam footage is asked to contact Dufferin County OPP at 1-888-310-1122.
Victim services are being offered to any witnesses by Caledon/Dufferin Victim Services at 905-951-3838.