This is the one page in this guide where we can’t give you a clean answer — because, as of this writing, nobody fully can.
Vietnam’s traditional position, under the 2008 Law on Vietnamese Nationality, was a strong single-citizenship principle: acquiring a foreign nationality was grounds for losing Vietnamese citizenship, with narrow exceptions carved out mainly for overseas Vietnamese returning to invest or specific government-approved cases.
An amendment passed in 2025 moved Vietnam toward a more permissive dual-citizenship stance — but the publicly available English-language coverage of the amendment describes its direction and intent more clearly than its precise mechanics for an ordinary private citizen who naturalises abroad for work or study, as opposed to categories like overseas-investment returnees that the law has historically prioritised.
Treat this as unresolved, not settled. If you’re a Vietnamese citizen planning to naturalise in Germany or elsewhere, verify your specific situation directly with a Vietnamese consulate before assuming either outcome — that you’ll automatically lose your citizenship under the old rule, or automatically keep it under the new one. Vietnam is the one country in this guide where we won’t state a confident rule, because the available sourcing doesn’t support one yet.