To report the findings from a unique analysis of naturally occurring data regarding self-harm behaviour generated through the global social media site, Twitter.Self-harm behaviours are of global concern for health and social care practice. However, little is known about the experiences of those who harm and the attitudes of the general public towards such behaviours. A deeper, richer and more organic understanding of this is vital to informing global approaches to supporting individuals through treatment and recovery.Exploratory, qualitative design.Three hundred and sixty two Twitter messages were subject to inductive thematic analysis.Five themes were identified: 1) celebrity influence, 2) self-harm is not a joke (with sub-themes of you wouldn't laugh if you loved me and you think it's funny, I think it's cruel), 3) support for and from others, 4) eating disorders and self-harm and 5) videos and personal stories.The findings indicate that self-harm behaviour continues to be largely misunderstood by the general public and is often the source of ridicule which may contribute to delays in accessing treatment. Whilst Twitter may also provide a source of valuable support for those who self-harm, the sense of community, relatedness and understanding generated by such support may contribute to normalising self-harm and perpetuating the behaviours.Our understanding of the complexity of, aetiology and most effective treatment options for self-harm behaviours are still unclear. The findings demonstrate that there is a critical opportunity to conduct further qualitative research to better understand self-harm and to utilise this valuable and internationally relevant data to support the development of effective public education campaigns and personally tailored treatment options. This article is protected by copyright. All rights reserved.