High levels of self-disclosure on different Social Media platforms are part of our everyday lives nowadays. Users tend to share detailed information about their personal lives willingly while often underestimating its negative consequences. Previous studies emphasize the complexity of the processes of online self-disclosure. Our aim with this current research is to examine how online self-disclosure is influenced by different psychological factors: the attitude towards the value of the users’ own data, perceived control over personal information and perceived risks associated with sharing on Social Media, with a multimethod study. In Study 1, a qualitative approach was introduced (N = 37), in Study 2, we conducted an online survey on a representative sample (N = 1597). In Study 1, we found that participants often underestimate the value of their own personal data and its usability by others. This (incorrect) interpretation gives them an increased sense of confidence about the security of their personal data in online contexts and facilitates them to share personal information on Social Media. In line with this, in Study 2 we found that the more the participants engage in self-disclosure on Social Media, the less risky they perceive their online activity. This suggests, the importance of sharing may overwrite the risks of sharing. Our results also show that higher engagement in online self-disclosure comes with a higher sense of control, which in turn decreases risk perception on Social Media sites. In sum, processes of self-disclosure on Social Media are influenced by not just the users’ sense of control and risk perception but their perceptions towards the value of their own personal data.