The incident happened on Burnley Road, Friendly, at 7.42am and the main road was closed for several hours until 10.30am causing major disruption for commuter travelling to work in Halifax with long tail backs in both directions.
The number M7 bus, which ferries pupils from the Upper Calder Valley to North Halifax Grammar School, Illingworth, collided with road works, hit a stationary van, collided with an oncoming pick-up truck, before shunting into four stationary vehicles.
No one was injured as a result of the incident but the driver of the bus was taken to hospital and a lamp post was also damaged.
Head teacher at the school Mr Graham Maslen said: "The students behaved in a very responsible way and received praise from both the emergency services and the Metro bus people. They didn't panic and left the bus in an orderly fashion and waited for another bus to pick them up.
"A few of them suffered whiplash and a bit of stiffness but there were no major injuries. We offered them counselling when they arrived at the school to help them deal with the trauma because some of them were clearly shocked. Some of them went back to class and some went home.
"The cause of the accident is being investigated and we look forward to hearing what it has to say."
A spokesman for West Yorkshire Fire Service said they believed the children on the bus had escaped unharmed because they were all wearing seatbelts.
The police, fire crews and the ambulance service attended the scene.
Anyone who witnessed the incident is asked to contact the police on 0845 6060606.