The objective of this research is to develop and validate a conceptual model of social networks user’s commitment. We have identified three antecedent variables of user’s commitment: social interaction, trust and self-expression, and user interaction and enjoyment as consequences of commitment. Firstly, we applied an exploratory factor analysis to validate the internal construct of the commitment. Secondly, we use the maximum likelihood estimation method for the confirmatory factor analysis. The measurement model provided an acceptable fit to data. 15 hypotheses were proposed in our model, 11 were supported by the data analysis and 4 were rejected.