The horserider sustained suspected arm and spinal injuries after she was reportedly thrown, landing underneath the horse she was riding, who also fell.
It is believed the horse was spooked by cattle.
The Bundaberg-based helicopter, which was tasked around 11am met Queensland Ambulance Service on a roadside near the scene of the accident.
A Flight Intensive Care Paramedic on-board the helicopter treated the teen before flying her to Bundaberg Base Hospital.
She travelled in a stable condition.