Nine of the injured were taken to Kojonup Hospital with minor injuries while a woman aged in her 30s was airlifted by the RAC rescue helicopter to Bunbury Hospital.
Her injuries are not life threatening.
The crash happened on Albany Highway near Boscabel shortly before 3pm.
The highway was closed in both directions to allow the rescue helicopter to land at the crash site.
In other crashes, the police dog squad has been sent to the scene of a crash in Dianella this afternoon.
A man’s car and an elderly woman’s vehicle collided on Grand Promenade about 2.40pm.
Police are searching for the driver who fled after the crash.
The elderly lady suffered an arm injury.
A teenager has been taken to Fiona Stanley Hospital after he was hit by a car in Langford at 2.50pm.
The teen was crossing at the Nicholson Road and Langford Avenue intersection when he was hit.
His injuries are described as non life-threatening.
Meanwhile, a mother and her three children had a lucky escape when their car was hit by a truck in Champion Lakes shortly after 3pm.
The woman’s vehicle and the truck collided on the Tonkin Highway, with all four sustaining only minor injuries in the crash.