The demand for the inclusion of a mental health measure for general health and well-being surveys in developing countries is increasing. There have even been calls for mental health to be added to the influential Demographic and Health Surveys. To meet this demand, the World Health Organization (WHO)-recommended Self-reporting Questionnaire 20 items (SRQ 20) has now been widely used and validated in many cultural contexts. Owing to low literacy levels in some countries, the questionnaire is usually interviewer-administered. A 4-country longitudinal study of child poverty called ‘Young Lives’ conducted in Peru, Ethiopia, India, and Vietnam included measurement of maternal mental health using the SRQ 20. No previous community-based study of mental health has been conducted in Vietnam. There was a need to test the validity and reliability of the SRQ 20 in this country, where very little is known about common mental disorders and their determinants. This paper presents the results of the tests and identifies a cut-off point to determine cases for future studies that use the SRQ 20 in Vietnam.