Background Self-harm is a major public health problem yet current healthcare provision is widely regarded as inadequate. One of the barriers to effective healthcare is the lack of a clear understanding of the functions self-harm may serve for the individual. The aim of this review is to identify first-hand accounts of the reasons for self-harm from the individual's perspective. Method A systematic review of the literature reporting first-hand accounts of the reasons for self-harm other than intent to die. A thematic analysis and 'best fit' framework synthesis was undertaken to classify the responses. Results The most widely researched non-suicidal reasons for self-harm were dealing with distress and exerting interpersonal influence. However, many first-hand accounts included reasons such as self-validation, and self-harm to achieve a personal sense of mastery, which suggests individuals thought there were positive or adaptive functions of the act not based only on its social effects. Limitations Associations with different sub-population characteristics or with the method of harm were not available from most studies included in the analysis. Conclusions Our review identified a number of themes that are relatively neglected in discussions about self-harm, which we summarised as self-harm as a positive experience and defining the self. These self-reported "positive" reasons may be important in understanding and responding especially to repeated acts of self-harm.