The emergence of Facebook’s suicide prevention algorithm has prompted discussion around whether social media platforms have a role to play in public health surveillance. Concerns have been raised about an entity that is not a public interest health authority collecting and acting on the private health information of its users, particularly sensitive data like an individual’s mental health status. Mental illnesses are still heavily stigmatised, despite continued efforts to normalise these conditions in some areas of the world. Depending on a user’s geographic location, the ramifications of the suicide detection algorithms generating false positives for suicide risk could have severe consequences. The present chapter continues this discourse by examining the ethical implications of Facebook’s suicide prevention algorithm from privacy, legal, and cultural perspectives.