You need a visa for Türkiye if you have a Vietnamese passport

Travelers need a visa to visit Türkiye for Business or Tourism. Travelers who have a valid visa or residence permit for a Schengen country, the United States, the United Kingdom, or Ireland are eligible for an Electronic visitor visa. A Türkish eVisa is the fastest and easiest way of obtaining a visa for Türkiye because travelers can submit their application and supporting documents online. Once the application is approved, travelers receive their eVisa confirmation electronically. Travelers must also have a round-trip ticket with Turkish Airlines or Pegasus Airlines to be eligible for an eVisa. Travelers who don’t have a supporting document require a Visitor visa. A Visitor visa is typically a stamp or sticker added to the passport. Travelers must obtain this visa from a local embassy, consulate or visa center before traveling. For all other visas, visit the government site.