nonsuicidal self-injury (nssi) is a direct and deliberate act that involves damage to one´s body tissues without suicidal intent. research shows that it is maintained by four reinforcement processes (automatic positive and negative, social positive and negative) and to be related to insecure types of attachment styles. however, whether there is a relationship between attachment styles and the reinforcement functions is unknown. participants (n = 753; age m = 36.01 years, sd = 12.58) recruited from the general community of canada and usa were classified into the nssi group (participants with at least one nssi act in their lifetime; n =358) and the control group (participants with no history of nssi; n =395). results indicated that participants in the nssi group endorsed anxious attachment style to a greater degree than the control group. in contrast, the control group endorsed secure attachment style to a greater degree than the nssi group. those with anxious attachment style reported that they engaged in nssi for reasons related to automatic negative reinforcement and automatic positive reinforcement, indicating that self-harming among these individuals serves an emotional regulation purpose. besides anxious attachment, sex was found to be another critical factor to consider in predicting the function of nssi. women and those with anxious attachment style were more likely to endorse nssi automatic positive and negative functions, while the men and those with depression were more likely to endorse nssi social negative functions. overall, the findings point to the importance of anxious attachment style in predicting the reasons for nonsuicidal self-harm. these findings and their implications are discussed with limitations of the study in mind.