This present study aims to investigate direct and indirect factors affecting willingness to communicate (WTC) in L2 by using Facebook. The emergence of Computer Mediated Communication (CMC) and Social Networking Sites (SNSs) such as Facebook (FB) provides the considerable changes in teaching and learning. Learning which is not only carried out in the classroom, but also out of the classroom. A new trend of using Social Networking Sites (SNSs) has been highlighted recently to prompt learners’ L2 WTC. 156 participants of university students of English Department participated by filling out a set of questionnaire with a 5-point Likert-scale encompassing students’ perception, motivation, communicative self-confidence (CSC), and Willingness to Communicate (L2 WTC). The participants are second semester English students from private and state universities in three cities in Indonesia: Surabaya, Bali, and Malang. Data collection and analysis used a software package, AMOS 20, to gauge the magnitude of the factors affecting L2 WTC by using FB platform. The finding shows that there are considerable effects on perception and motivation mediated by communicative self-confidence to WTC. While, communicative self-confidence shows the strongest predictor on L2 WTC.