Certain aspects of personality can increase an individual’s susceptibility to, or exacerbate, loneliness. Pathological narcissism, involving difficulty in the maintenance and regulation of one’s self-image, is one such personality constellation that may influence the experience of loneliness. This chapter reviews the concept of pathological narcissism—including the domains of narcissistic vulnerability and grandiosity—and outlines its connection with loneliness from theoretical, empirical, and clinical perspectives. We review research on the relationship between pathological narcissism and loneliness, including findings on the salient aspects of interpersonal functioning. Although several studies clearly demonstrate a link between narcissistic vulnerability and loneliness, further research is needed to extend our understanding of this relationship. Finally, clinical implications of the narcissism–loneliness connection are discussed.