Eight other people were injured including one in critical conditions.
The truck was traveling on National Highway 5 from Hanoi when it hit a group of commune officials who were walking along the road.
They were returning to work after burning incense at the local martyrs’ cemetery.
The accident happened at around 2 p.m. in Kim Thanh District in Hai Duong, around two hours to the east of Hanoi.
An eyewitness said the victims "were walking in the motorbike lane on the opposite direction with the truck."
The truck driver fled the scene after the accident, which the police are investigating.
Road crashes are a leading cause of deaths in Vietnam, killing almost one person every hour. A total of more than 18,720 traffic accidents occurred in 2018, killing 8,244 people and injuring nearly 14,800, according to the National Traffic Safety Committee.
Earlier this month, four people died and 16 others were injured in southern Long An Province after a truck slammed into motorbikes waiting at a traffic light. The 32-year-old truck driver was later found to have been high on liquor and heroin.