The current study aims to investigate if venting anger reduces or increases aggression. Therefore, we allowed venting anger and measured its effect on aggression after two different anger provocation paradigms in a sample of forensic psychiatric offenders (FPO, N = 45) and penitentiary offenders (PO, N = 22). These provocation paradigms included an Articulated Thoughts in Simulated Situations (ATSS) comprising anger stories, and a harassing body opponent bag (BOB) measuring punching force. To determine aggression pre/post provocation, implicit anger and self-reported aggression was assessed. Further, the relation between provocation paradigm response, aggression, and psychopathy was evaluated. Results indicate that venting anger reduces aggression in FPO, but not in PO, where even evidence for increase in one aggression index was found. Furthermore, groups differed in immediate responses during provocation, with FPO showing significantly more verbal aggressive responses during ATSS but less physically aggressive responses during BOB than PO. Moreover, results show a correlation between automatic cognitive anger biases during provocation and psychopathy in FPO. In PO, aggressive behavioral intentions and anger control problems during provocation were both related to self-reported aggression. For clinical practice, ATSS could be utilized as a paradigm exploring the actual state of specific cognitive biases toward anger.