The accident at Nyakairu center, 15 kilometres from Naivasha town, occurred after the truck hit an incoming matatu head-on, killing four passengers.
The driver of the lorry that was heading to Naivasha also died on the spot. Scores of passengers in the 2NK Sacco matatu that was heading to Nairobi were injured.
According to the Naivasha Road Safety Association chairman James Kabono, the lorry driver was to blame for the accident.
"Five people have died on the spot and scores of others have been injured and rushed to Naivasha sub-county hospital," he said.
READ MORE
One killed in tanker explosion on Southern Bypass
Tears, sorrow as US-based family bids farewell to three siblings killed in road crash
Police recruit killed, 24 injured as car hits trainees
Sh8.6m raised to support Kenyan family that lost three siblings in tragic crash