Purpose-This study aims to understand the impact of users privacy concerns on their acceptance of social networking web sites (SNWs).Design/methodology/approach-This paper develops two research models,with privacy concern conceptualized either as an antecedent of acceptance intention,or as a moderator of the relationships in the technology acceptance model (TAM).Using a survey questionnaire,empirical data were collected from 428 undergraduate college students.Structured equation modeling was used to test the validity of the proposed research models.Findings-The privacy concerns of the research respondents were found to be statistically significant.However,they did not directly affect users acceptance of social networking web sites.Instead,privacy concerns did moderate the effects of perceived usefulness,and perceived ease of use,on users intention to continue to use SNWs.Research limitations/implications-The study identifies the theoretical foundations of privacy and privacy concerns in the context of SNWs.This empirical study,based on an established theoretical foundation,will help the research community to gain a deeper understanding of the impacts of privacy concern in the context of social networking.Practical implications-The findings of this study can provide SNW operators with useful strategies and tactics to enhance users acceptance depending on their level of privacy concern.Originality/value-With the worldwide rapid growth of SNWs,there have been ongoing concerns about how users private information is viewed or used by others.This study provides much needed empirical evidence about the impact of privacy concerns on users acceptance of SNWs.