Despite the effectiveness of prolonged exposure (PE) and cognitive processing therapy (CPT) for posttraumatic stress disorder (PTSD) in reducing symptoms of PTSD and co-occurring symptoms, emerging research suggests continued mental health service utilization (MHSU) following the completion of these interventions. Reasons for continued MHSU remain unknown despite its relevance to PE/CPT outcomes and implementation. The present study employed a mixed methods approach to explore rates and reasons for VA MHSU post PE/CPT. A national sample of 5,634 U.S. veterans who completed either PE or CPT were identified to quantitatively determine the frequency, type, and location of MHSU in the 12 months following PE/CPT completion. A random subsample of 60 veterans completed semistructured qualitative interviews to explore reasons for MHSU post PE/CPT. Findings suggest high MHSU; 98.4% of veterans attended at least one mental health appointment in the year following completion of PE/CPT, with an average attending 27.64 appointments in the year following treatment completion. Qualitatively, veterans, particularly those with low-to-moderate residual symptoms, described a preference for additional treatment to continue practicing and applying skills learned in treatment. Veterans expressed low self-efficacy to maintain treatment gains without support and accountability from their therapists and viewed ongoing treatment as a safety net until they felt more confident in their skills and stability of gains. Veterans with high residual symptoms indicated needing additional PTSD-specific treatment or treatment for a co-occurring condition. Notably, some veterans reported no additional treatment needs, despite continued engagement in care. Evidence-based strategies for facilitating self-efficacy and ongoing application of PE/CPT principles posttreatment are needed. (PsycInfo Database Record (c) 2024 APA, all rights reserved).