Duong Thi Thuy Trang, 34, pleaded guilty to holding passports that did not belong to her, a punishable offence under Malaysia's Passport Act.
Local police found the passports in a house in Rompin District, Pahang State on February 3, Malaysian National News Agency Bernama reported.
The report did not say how and why Trang was in possession of other passports.
People in Southeast Asia can travel across the region without having to apply for a visa, but they are only allowed to stay for 30 days as tourists.
In recent years, Vietnamese workers, mainly women, have visited neighboring countries like Thailand, Singapore and Malaysia and stayed on to work illegally.
Many of them have been caught, detained and deported.