© Johannes Plenio
The victims were struck as they sheltered outside a house during a heavy downpour.
Njoro sub-county Police Commander Mohammed Huka said the incident occurred at about 6pm.
Mr Huka said among the dead were four men, while a woman, who suffered serious injuries, was rushed to Nakuru Level Five Hospital in critical condition.
The bodies were taken to Nakuru County Hospital mortuary.
"The victims were struck outside a house as they waited for the rains to subside," said Mr Huka.
He urged the residents to stay indoors when it rains to avoid such tragedies.
Heavy rains pounded most parts of Nakuru town and its environs on Saturday evening, causing floods in some areas.
Comment: Also recently across the planet at least 4 people were killed by lightning strikes in Bangladesh, 2 individuals in Khammam, India, a tourist and 2 siblings in the Philippines, a woman in Nepal and a herbalist in Nigeria.