The article discusses the need for a standardized, empirically validated measure of deliberate self-harm (DSH), a behavior increasingly studied by clinical researchers. Despite growing interest, there is no consensus on how to define and measure DSH. The Deliberate Self-Harm Inventory (DSHI) was developed to address this gap. Preliminary data show that the DSHI has high internal consistency, adequate construct, convergent, and discriminant validity, and good test-retest reliability. DSH is defined as the deliberate, direct destruction or alteration of body tissue without suicidal intent, resulting in injury. It is considered a non-adaptive coping mechanism or emotion regulation strategy. DSH is associated with negative outcomes, including interference with therapy and relationships, and can unintentionally lead to death. Researchers suggest that DSH is increasing in prevalence. However, there is inconsistency in the literature regarding definitions of DSH, with terms like self-injury and self-mutilation used interchangeably. Some researchers distinguish between DSH and suicide-related behaviors, while others do not. The article reviews various definitions of DSH, provides an integrative definition, and begins to explore the psychometric properties of the DSHI. It also notes that DSH is often confused with suicide attempts, and that overdoses are excluded from DSH definitions due to ambiguity. The article concludes that DSH is a complex behavior with significant clinical implications, and that a standardized measure is needed to advance research.The article discusses the need for a standardized, empirically validated measure of deliberate self-harm (DSH), a behavior increasingly studied by clinical researchers. Despite growing interest, there is no consensus on how to define and measure DSH. The Deliberate Self-Harm Inventory (DSHI) was developed to address this gap. Preliminary data show that the DSHI has high internal consistency, adequate construct, convergent, and discriminant validity, and good test-retest reliability. DSH is defined as the deliberate, direct destruction or alteration of body tissue without suicidal intent, resulting in injury. It is considered a non-adaptive coping mechanism or emotion regulation strategy. DSH is associated with negative outcomes, including interference with therapy and relationships, and can unintentionally lead to death. Researchers suggest that DSH is increasing in prevalence. However, there is inconsistency in the literature regarding definitions of DSH, with terms like self-injury and self-mutilation used interchangeably. Some researchers distinguish between DSH and suicide-related behaviors, while others do not. The article reviews various definitions of DSH, provides an integrative definition, and begins to explore the psychometric properties of the DSHI. It also notes that DSH is often confused with suicide attempts, and that overdoses are excluded from DSH definitions due to ambiguity. The article concludes that DSH is a complex behavior with significant clinical implications, and that a standardized measure is needed to advance research.