The fire, which occurred at 3 a.m. in Russey Keo District, lasted until the morning, but there were no casualties, Vietnam's foreign ministry said in a statement.
Initial investigation has led to speculation that the fire was caused by an electrical fault in one of the destroyed houses, the Khmer Times reported.
Vietnam's Ministry of Foreign Affairs said it has sent donors' aids to the affected families and said it would cooperate with authorities to resolve the fire's consequences.