
The accident took place on Paholyothin Road in the Mae Chan district at about 6.40am.
Most students sustained minor injuries and were allowed to return home following treatment, but some remained hospitalised as of press time.
The van had collision insurance covering its passengers.
Driver Yongyut Thongkorn said he was trying to overtake a car in front of him when he lost control of his vehicle.
Chiang Rai Governor Narongsak Osotthanakorn urged motorists to drive carefully as the rain had made roads very slippery.