The students of Nambale Boys High School were on their way to the lake when the accident occurred at about 11am.
“Four students died on the spot while the fifth succumbed while being taken to hospital,” Traffic Commandant Samuel Kimaru said.
According to police and witnesses, the accident occurred when the school bus attempted to overtake a light truck. In the process, the bus driver lost control and hit the truck from behind, ripping part of it.
The bus was carrying 29 students and four teachers at the time of the accident. Six of the injured students were said to be in critical condition.
All the injured are being treated at the Nakuru Provincial General Hospital.
Cases of road carnage have been on the increase lately in the country, with up to 3,000 people killed annually.
Kimaru has appealed to motorists to be cautious whenever they are on the road to help minimise road accidents.