Police said that the explosion took place when a vehicle hit a mine in Qaysar District of Faryab Province, killing all five people.
The identities of the victims were yet to be known.
Officials have blamed the Taliban militants for the attack.
No one has claimed responsibility for the attack.
Many civilians have lost their lives either in Taliban bomb explosions or in NATO airstrikes and ground attacks.
The bloody violence has become routine despite the presence of some 150,000 foreign troops in Afghanistan.