Loneliness is a painful affect state concerning perceptions of inadequate social relationships, involving the subjective experience of being isolated, excluded, or alone. Loneliness is increasingly recognized as a major threat to individuals’ health and wellbeing, with research investigating contributors to loneliness that include personality domains. Previous cross-sectional research has indicated pathological narcissism – in particular, higher levels of narcissistic vulnerability – to be associated with loneliness. This presentation will highlight existing knowledge and new research regarding the relationship between pathological narcissism and loneliness. Specifically, the present study was aimed at investigating whether pathological narcissism predicts loneliness (i.e., at downstream assessment), and whether impaired self- or interpersonal functioning, reflecting the DSM-5 alternative model of level of personality functioning, would account for this relationship. A sample of community members who had recently sought mental health care was recruited online to complete self-report assessments. Participants (N=298) completed measures of narcissistic vulnerability, narcissistic grandiosity, and self- and interpersonal functioning dimensions; a brief measure of loneliness was also completed, including at a second time point two months later. Zero-order correlations indicated no significant associations between loneliness and two types of narcissistic grandiosity. Loneliness was positively associated with narcissistic vulnerability and with each domain of impaired self- and interpersonal functioning: identity, self-direction, empathy, and intimacy. Mediation analysis examined impaired self-and interpersonal functioning as parallel mediators of the association between narcissistic vulnerability (time 1) and loneliness (time 2), controlling for baseline loneliness. Results add to evidence suggesting that narcissistic vulnerability may be a significant predictor of loneliness, and suggest impaired interpersonal abilities as an explanation for this relationship. Clinical considerations regarding loneliness and pathological narcissism will be discussed, along with study limitations and future research directions.