Alcohol intoxication has been associated with deliberate self-harm (DSH). However, the mechanisms underlying this relationship are poorly understood. The primary purpose of this study was to examine pain tolerance (PT) as a potential mechanism underlying the relationship between alcohol intoxication and DSH. The secondary aim was to determine if borderline personality (BPD) features moderate the mediational model. This model was tested using secondary data of 210 non-alcohol dependent men and women (Mage = 26; SD = 6.97) who consumed a drink containing sufficient alcohol to produce average blood alcohol concentration (BAC) ranging from .000 through .100. Participants then engaged in a validated laboratory self-harm task (The Self-Aggression Paradigm). Results supported the notion that PT mediates the relationship between BAC and DSH. BPD moderated the indirect path between PT and DSH but not BAC and PT. This effect was prominent for men versus women. Clinical implications and future directions are discussed.