Introduction: Waterpipe use is a significant health concern in low- and middle-income countries like Viet Nam, yet there is a lack of research on factors that may influence use and self-efficacy to quit among adults. Aims: This study examined the relationship between social norms related to waterpipe use and self-efficacy to quit among male waterpipe smokers in Viet Nam. Methods: A cross-sectional survey was conducted with 214 adult male waterpipe smokers enrolled in a large cluster–randomised controlled trial conducted in a rural province in Viet Nam. Associations between social norms related to waterpipe smoking and the participants’ confidence to quit waterpipes were assessed using hierarchical regression models to account for differences among study sites and other covariates. Results: Self-efficacy to quit smoking was positively associated with immediate family members’ not minding participants smoking and with extended family's encouragement to quit smoking. Conclusions: The findings suggest the need for a more comprehensive understanding of the functions and characteristics of the social context of waterpipe smoking, including the social networks of waterpipe smokers, to inform effective cessation interventions for waterpipe smokers.