The incident in the Salama area in the east of the country took place after midnight on Saturday when a truck driver failed to overtake another truck.
It caused a collision with other vehicles, including a van carrying pilgrims, according to local police.
The driver and 16 passengers in that van, most of them women, died at the scene, police said.
The pilgrims were going to a prayer site in Nakuru County, west of Nairobi, said Martin Kivuva, Archbishop of the Catholic Archdiocese of Mombasa.
Mr Kivuva said in a statement that he and others were “saddened with lots of grief” over the deaths.
“Let us pray for the repose of their souls as we pray for their families,” he said.
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Kenya’s president William Ruto said he was “deeply saddened” by the tragic incident, which took place on National Prayer Day.
“Our heartfelt condolences go to the families, friends, parishioners and the entire Catholic community who are mourning this painful loss,” Mr Ruto added.
Road accidents are common in Kenya and the wider East African region, where roads are often narrow and filled with potholes. Police often blame road incidents on speeding drivers.
In August last year, a bus carrying mourners back home from a funeral in southwestern Kenya overturned and plunged into a ditch, killing 25 people and injuring several others.
