The emergency services were alerted to the incident in the Pine Grove area of Cimla at about 18:15 BST.
The air ambulance landed on the grounds of Crynallt Junior school and transported the girl to Morriston Hospital in Swansea.
A South Wales Police spokesman said she suffered bruising to her ankle and head.
Cimla Councillor John Warman, who attended the scene of the incident, estimated the girl to be about five years old.
He praised the emergency services, which he said "were very prompt" in arriving.
A young girl was airlifted to hospital after being hit by a car on a housing estate in Neath Port Talbot on Sunday.