The deaths were reported from several districts after sudden storms brought heavy rain and intense lightning, Reuters reported.
Most of the victims were farmers working in open fields and laborers caught in exposed areas, local authorities said. Several other people were injured and taken to nearby hospitals, with some in critical condition.
Lightning kills hundreds of people every year in Bangladesh, which declared lightning strikes a natural disaster in 2016 after more than 200 people died in the month of May alone, including 82 people on a single day.
Experts say the rise in fatal lightning strikes is linked to deforestation, which has led to the disappearance of many tall trees that previously helped draw lightning away from people.
Lightning-related fatalities are common during the pre-monsoon months of April to June, when rising heat and humidity create unstable weather conditions.