This study aimed to identify how frequently suicidal individuals disclosed their ideation, assess which sources were perceived to be most helpful and identify correlates of disclosure and source helpfulness. A cross-sectional survey was conducted with 1,616 Australian adults reporting suicidal ideation in the past 12-months. Participants were recruited from social media and reported on their disclosure of suicidal thoughts to formal and informal sources. 39% of participants did not disclose to anyone, while 47% disclosed to an informal source and 42% to a health professional. The responses of psychologists and counsellors were perceived to be the most helpful, while parents and hospital-based health professionals were perceived to be the least helpful. Severity of suicidal thoughts, younger age, and a suicide attempt in the past 12-months were associated with greater likelihood of disclosure, while participants who were younger, linguistically diverse, had greater suicidal ideation or personal stigma were less likely to perceive the response of a GP to be helpful. This study demonstrates that non-disclosure of suicidal thoughts is frequent and that the response received to a disclosure may not always be perceived to be helpful. Further research is needed to identify how best to support individuals who disclose suicide.