It surpassed four other rivals Cambodia, China, Laos and Thailand to claim the title, the organizing board announced Thursday.
The awards were based on votes cast by industry professionals, the media, and consumers.
Singapore was named winner of Asia's best cruise destination category.
World Cruise Awards, a sister event of World Travel Awards, serves to recognize, reward and celebrate excellence in the global cruise sector.
Vietnam has a dense river network containing 2,360 rivers with a total length of more than 10 kilometers (6.2 miles).
In recent years, luxury river cruise tours passing famed attractions and ancient temples have become a not-to-be-missed experience while visiting Vietnam.