Narcissism can lead to various interpersonal problems. However, the characteristics of social decision making in trait narcissism and the cognitive and affective underpinnings are poorly understood. We employed established game theoretical paradigms to investigate different facets of social behavior in participants (N = 122; 41 female, mean age = 30 years) with a wide range of scores on the Pathological Narcissistic Inventory. Interpersonal traits, attitudes, and emotions were assessed as potential mediators of behavioral differences. High narcissism scores were related to lower generosity, especially when this could result in being punished. This maladaptive behavior was fully mediated by reduced perspective-taking abilities in narcissism. Also, narcissism scores predicted higher levels of punishment behavior, driven by higher levels of experienced anger. Hence, the difficulties narcissists face in interactions may be due to their reduced perspective-taking skills and resulting reduced generosity as well as enhanced anger-based retaliation behavior.