Understanding the role of narcissism in sexually motivated serial killers is crucial for uncovering the psychological mechanisms behind their actions and aiding effective profiling, prevention strategies, and interventions. This study investigated whether dimensions of trait narcissism are present in sexually motivated serial killers and how these dimensions co-occur. Based on the Narcissistic Admiration and Rivalry Concept (NARC) and the Vulnerable Isolation and Enmity Concept (VIEC), we distinguished between different dimensions of grandiose (grandiose admiration and rivalry) and vulnerable (vulnerable isolation and enmity) narcissism. Confessions and interrogation interviews from 45 male serial killers, either publicly available or obtained upon request, were analyzed using qualitative content analysis. Findings showed a significant presence of grandiose and vulnerable narcissism, with vulnerable enmity (84%) and grandiose admiration (76%) being most prevalent. The results can contribute to a framework for targeted prevention strategies and lay the groundwork for future research on narcissism’s intersection with psychopathy, impulsivity, and other personality traits in serial homicide.