The present article focuses on the validation of the Questionnaire of Social Representations about the Functions of Deliberate Self-Harm for adults. The understanding of the social representations about deliberate self-harm can be relevant for clinical intervention and prevention. However, there is still a lack of instruments to assess these representations. The basis for this instrument was the translation of the Inventory of Statements About Self-Injury. To complement this instrument, we conducted semi-directive interviews with adults without deliberate self-harm and analysed the Portuguese written press. Results from these studies complemented the questionnaire with new items and functions. Study 1 consisted of an exploratory factor analysis with a sample of 462 adults. Results revealed a two-factor structure of interpersonal and intrapersonal dimensions. After item reduction, the factorial analysis of the independent functions was also acceptable. This structure was then corroborated in Study 2 by a confirmatory factor analysis with a new sample of 474 adults, revealing an acceptable model fit. This questionnaire presents a relatively solid structure and is based on acceptable psychometric properties, which allows its use in future research.