Location-based social network sites (LBSNS) are the integrations of social network service and location-based service. In this study, we examine two opposite factors, the benefits and privacy concerns, which affect the disclosure intention of users on LBSNS in a mobile environment. We utilise the privacy calculus perspective framework on the disclosure intention of location information. Also, the Big Five model is used to examine the impacts of dispositional factors, such as personality traits, on the concern for privacy. The privacy control, legislation awareness and privacy invasion are control variables for both disclosure intention and privacy concern. Data were collected from 298 respondents residing in Ho Chi Minh City, Vietnam. The results indicate that the legislation awareness does not seem to exert a significant influence on both privacy concerns and disclosure intention; it can be explained by the poor effectiveness of legislation in a developing country like Vietnam. However, we clearly found that the benefits and privacy concerns have the opposite influence on behavioural decisions of social network users, with the former positively affecting disclosure intention and latter negatively. Moreover, findings in the study show that perceived benefits such as connectedness, locatability and personalisation have stronger effects than privacy concerns do.