In this study we investigated 3 domains of emotional functioning--emotion dysregulation, distress tolerance, and experiential avoidance--in young adult outpatients with borderline personality disorder (BPD) symptoms. Participants were 40 young adult outpatients at a university counseling center who reported current suicidal ideation and met diagnostic criteria for BPD or experienced subthreshold BPD symptoms (i.e., met diagnostic criteria for 3 or 4 symptoms). Participants completed 3 self-report measures of emotional functioning-experiential avoidance (Acceptance and Action Questionnaire-2; Bond et al., 2011; Hayes et al., 2004), emotion dysregulation (Difficulties in Emotion Regulation Scale; Gratz & Roemer, 2004), and distress tolerance (Distress Tolerance Scale; Simons & Gaher, 2005)-and a behavioral measure of distress tolerance (Paced Auditory Serial Addition Task-Computerized; Lejuez, Kahler, & Brown, 2003), in addition to self-report measures of depression and BPD symptom severity. Partial correlations demonstrated that both emotion dysregulation and experiential avoidance were significantly associated with BPD symptom severity after accounting for depression. However, neither the self-report nor behavioral measure of distress tolerance were related to BPD symptom severity. A regression analysis with emotion dysregulation and experiential avoidance as independent variables revealed that only experiential avoidance was significantly associated with BPD symptom severity after controlling for depression symptoms. The current findings suggest that experiential avoidance may be a central process in BPD symptom severity. Future research directions are discussed.