The ways in which educational practitioners represent themselves on social networking sites (SNSs) continue to provoke discussion and potential controversy. This study investigates how English as a Foreign Language (EFL) teachers in Vietnam manage their self-presentations within SNSs for professional learning purposes. Participants in this mixed methods study included 19 teachers in four focus-group interviews, and 393 respondents to an online survey. We applied teacher identity to interpreting teachers' self-presentation on virtual platforms. Our findings reveal that although participants frequently use SNSs for professional learning, they prefer a lurking presence and less visible interaction. It is also evident that self-presentation on SNSs is not simply 'represented' or 'reflected'. Rather, these teachers prefer their self-presentation to fit with how they are perceived in Vietnamese society. Teachers' self-presentation within SNSs is thus robustly mediated by culture. The study contributes to the ongoing interest in teachers' increasing use of SNSs in their professional lives.