This study investigated whether there is a difference in self-disclosure on Facebook between employees of an Australian government organisation and an academic institution. We employed quantitative and qualitative approaches, including an online questionnaire of 216 participants and ten interviews. The two organisations were compared on organisational variables, and measures of Privacy Concerns, Privacy Behaviour and Propensity to Trust as potential predictors of self-disclosure. Privacy Behaviour and Propensity to Trust were significant predictors for the government organisation, whereas demographic and organisational factors were the main predictors for the academic institution. Furthermore, qualitative findings revealed that, whilst the government participants focussed on the costs of self-disclosure on Facebook, the academic institution participants focussed on the benefits of self-disclosure. These results provide preliminary support for our online self-disclosure model, and highlight the importance of considering different organisations and populations in studies of online self-disclosure and privacy.