The personal information shared on Facebook can expose individuals to increased risk such as cybercrime and identity theft. While the perception of risk associated with online self-disclosure is increasing, this may not translate into risk management behaviours. This study explored why individuals choose to self-disclose on Facebook, often in spite of the risks. It was hypothesised that a personality style accentuated by impulsive and anti-social behaviour would help to explain this risk-behaviour dichotomy. In other words, individuals who are more narcissistic with less self-control were predicted to expose themselves to more risk on Facebook. An online questionnaire was completed by 263 Australians. This study found that individuals who had less self-control and higher narcissism exposed themselves to significantly more risk on Facebook. Hence, this study found that narcissism and self-control play a meaningful role in the risk-behaviour dichotomy. These findings add to the body of literature on online self-disclosure.