Self-care and self-efficacy play an important role in predicting quality of life among patients undergoing hemodialysis, but there currently is a lack of an instrument in the Vietnamese language for assessing self-care and self-efficacy. This limits the ability of researchers to explore and determine the confidence patients have in their ability to perform relevant self-care activities. The purpose of this investigation was to assess the validity and reliability of the Strategies Used by People to Promote Health questionnaire-Vietnamese version. This cross-sectional study involved translation, validation, and cultural adaptation of the questionnaire into Vietnamese and a trial with 127 patients undergoing hemodialysis in Bach Mai Hospital (Hanoi, Vietnam). The questionnaire was translated by bilingual translators and validated by three experts. Internal consistency and confirmatory factor analysis were applied. This questionnaire demonstrated good content validity and a Cronbach’s alpha of 0.95 for the total scale. Confirmatory factor analysis of the three-factor model showed moderate model fit (comparative fit index = 0.84, Tucker–Lewis coefficient = 0.82, root mean square error of approximation = 0.09). Overall, this questionnaire exhibited acceptable validity and reliability for measuring self-care and self-efficacy among patients undergoing hemodialysis.