The district in central Bangladesh experienced thunderstorms on Friday afternoon under the influence of cyclone Fani.
The monster storm was poised to hit the country in the evening after crossing Odisha coast in India.
In Kishoreganj, two people were killed after being struck by lighting at Mithamain Upazila, three in Pakundiya, and one in Itna, police said.
One of the victims, a 7-year-old boy, was out for bringing back cattle.
Another was cutting grass for cattle while four others were working or returning from crop field, according to police.