Abstract: Introduction: Given the high frequency and persistence of suicidal thoughts and behaviors among individuals with borderline personality disorder (BPD), characterizing mitigating factors of risk is critical. Suicide-related coping (SRC; knowledge and confidence in using internal coping strategies and external supports to manage suicidal thoughts and urges) is beneficial for suicide risk management. However, SRC has not been characterized longitudinally in suicidal individuals with BPD. Methods: A clinical sample of 98 high-risk veterans (83% male; 21-73 years old [M = 44.7]) with BPD features was assessed in up to four waves over 1 year. Multilevel models evaluated between- and within-person relationships of SRC with thwarted interpersonal needs, depressive symptoms, hopelessness, and reasons for living. Results: Results found significant (p < 0.001) between- and within-person relationships between SRC and suicide risk and protective factors. Within-person heterogeneity accounted for ≥ 50% variance (between-person ≤ 50% variance). SRC's relationships with all outcomes were maintained when considering suicidal characteristics besides between-person SRC with depressive symptoms. Discussion: These findings suggest that SRC tracks with fluctuations in suicide risk and protective profiles over time in veterans with clinically meaningful BPD features, positioning it as a promising protective factor for suicidal thoughts and behaviors in this population.