<p>Looming provocation refers to a recently proposed negative cognitive style in which interpersonal slights are not seen just as isolated events but as threats gathering further momentum. Individuals high in this style assume provocations will escalate unless they stop them or strike first. Because this looming provocation mindset has recently been tied to a broad range of aggressive tendencies, the present research tests whether anger rumination is the cognitive process that channels these escalating provocation appraisals into aggressive action. A sample of 218 undergraduates completed the Looming Provocation Questionnaire (LPQ), Looming Cognitive Style (LCS) scale, Buss-Perry Aggression Questionnaire, and Anger Rumination Scale. Structural equation modeling evaluated the mediation model. Anger rumination fully mediated the associations between looming provocation and physical aggression, verbal aggression, and anger, and partially mediated its link to hostility (which also retained a direct link to looming provocation). Anger rumination mediated the association between looming provocation and aggression, illuminating a cognitive-affective pathway through which threat perceptions relate to aggressive behavior. The results point toward new targets for cognitive-behavioral interventions, anger management programs, and conflict resolution strategies aimed at reducing interpersonal aggression.</p>