Abstract: This study examined factors that contribute to self-disclosure motivation in social media users. The factors are: self-awareness, anonymity and demographic variables. We assume that self-awareness (public, private, surroundings), anonymity (un-link ability, un-observability, pseudonym) and demographic variables (gender and age) predict self-disclosure in social media user. Samples are 226 participants (age range from 15-25 years old) using purposive sampling technique. The measurements are: self-disclosure scale (Wheeles and Grotz), self-awareness scale (Govern and Marsch), anonymity scale (Lee, Choi and Kim). The result showed that there was a significant influence of self-awareness, anonymity and demographic variables on self-disclosure in social media users (26.5%).