Background: The COVID-19 pandemic, alongside the restrictive measures implemented for its control, may considerably affect people’s lives particularly vulnerable persons such as children, elderly and people with underlying diseases. This study aimed to assess the well-being of Vietnamese people after COVID-19 lockdown measures were lifted and life gradually returned to normal in Vietnam. Methods: An online survey was organized from 21 st to 25 th April 2020 among Vietnamese residents aged 18 and over. Data were collected concerning the participants’ health (...) status, COVID-19 preventive behaviour, and consequences of the preventive measures. The WHO-5 Well-Being Index was used to score participants’ well-being. Results: A total of 1922 responses were analyzed (mean age was 31 years; range: 18-76). Factors associated with a high well-being score included older age, eating healthy food, practising physical exercise, working from home, and adherence to the COVID-19 preventive measures. Female participants, persons worried about their relatives’ health, and smokers were more likely to have a low well-being score. Conclusions: The Vietnamese people continued to follow COVID-19 preventive measures even after the lockdown was lifted. Most respondents scored high on the well-being scale. However, the emergence of a new COVID-19 outbreak with an epicenter in Da Nang city is expected to increase public anxiety and mental health problems. It is clear that together with preventive measures, developing strategies to guarantee the well-being of the Vietnamese people’s is equally important. (shrink)