abstract: Those who have borderline personality disorder (BPD), and those who have subclinical levels of BPD features, experience distress and impairment in important life domains, especially in their interpersonal interactions. It is critical to understand the factors that alleviate BPD symptoms in order to help affected individuals lead healthier lives. Rejection sensitivity and sleep disturbance are two factors that may maintain or exacerbate BPD symptoms, yet new research indicates socially supportive relationships are related to symptom remission. While extensive research exists on the interpersonal impairments associated with borderline personality pathology, little research exists on how individuals with BPD or BPD features perceive and experience their social support. The present study examined the relationships between BPD features, perceived social support, sleep quality, and rejection sensitivity in a racially diverse, large sample of primarily college-aged individuals (N = 396). Results indicated that BPD features had a significant positive relationship with self-reported rejection sensitivity and a significant negative relationship with self-reported perceived social support. Additionally, BPD features had a significant positive relationship with sleep disturbance. Sleep disturbance did not moderate the relationship between BPD features and rejection sensitivity as expected; however, the regression of rejection sensitivity on BPD features and sleep disturbance was significant. Finally, sleep disturbance moderated the relationship between BPD features and rejection sensitivity. Results extend and replicate recent research findings on the possible mechanisms that may maintain and alleviate BPD symptoms. Furthermore, the moderating effect of sleep disturbance on perceived social support for those with higher levels of BPD features is unique to this study. / Dissertation/Thesis / Masters Thesis Counseling Psychology 2016