Extant research has tested the processes explicating how individuals use re-appraisal (an emotion regulation strategy) to down-regulate negative emotions, including anger. However, no research has tested how re-appraisal is related to aggressive behavior despite several theoretical claims regarding its relations. Three studies tested the general hypothesis that re-appraisal will be negatively related to aggressive behavior while also testing what variables moderate and mediate these relations. Using a cross-sectional design, Study 1 found that re-appraisal was negatively related to aggressive behavior and that re-appraisal significantly mediated the relations between known aggression-related variables (e.g., vengeance, anger) and several indices of aggressive behavior. Study 2 used an experimental design to further test the findings in Study 1. Employing a mixed factorial design, some participants were provoked, praised, or given no feedback from a same-sex "partner" on an essay writing task. Some participants were then given mitigating information - information that should cue re-appraisal processes - regarding the feedback prior to completing an aggressive and prosocial behavioral measure. Results showed that provoked participants who did not receive the information were significantly more aggressive than those provoked participants who received the information. Revenge motives significantly mediated these relations and trait levels of re-appraisal moderated these mediated effects. Study 3 was an intervention designed to reduce vengeance by teaching participants how to re-appraise. Results showed that participants who were low at baseline levels of re-appraisal and were in the intervention condition had the highest increase in re-appraisal. Most importantly, the largest decrease in vengeance was observed for participants who were in the intervention condition and had the highest increase in re-appraisal. Overall, these findings suggest that re-appraisal is negatively related to vengeance and aggressive behavior.