Abstract: Background: Posttraumatic stress disorder (PTSD) is a disabling condition costing the Veterans Administration (VA) $5 billion annually in disability compensation. Despite system-wide dissemination of Cognitive Processing Therapy (CPT) and Prolonged Exposure (PE) since 2007, only a small minority of veterans complete these treatments. We investigated the impact of sequenced treatment on initiation of and retention in CPT and PE across self-reported race and ethnicity, as well as recent heavy drinking and suicidal ideation (SI). Methods: VA administrative data were used to assess the impact of sequenced psychotherapy (SP), in which ≥ 8 sessions of non-trauma-focused individual (SPI) or group (SPG) psychotherapy was delivered before trauma-focused care, on initiation and retention in CPT and PE over two years from PTSD treatment initiation. Results were analyzed by self-reported race and ethnicity, heavy drinking (AUDIT-C ≥6), and SI (PHQ9 Q9>1). Results: Nationwide, 12.9 % of veterans who entered care for PTSD between 10/1/2014 and 11/30/2020 (n = 490,097) initiated VA-disseminated evidence-based treatment within 21 months (9.5 % CPT, 3.4 % PE). Among those, treatment retention (≥ 8 sessions) was 46.4 % and 42.3 %, respectively. SPI and SPG were associated with 0.4-6.8 % increases in CPT and PE initiation across racial/ethnic and risk groups. SPI was associated with increased CPT and PE retention of 8.0 % and 8.2 %; for SPG, retention increases were 3.4 % and 8.7 %. Strikingly, Hispanic White veterans with heavy drinking had 21.7 % increased CPT retention following SPG. Conclusions: Sequential individual and group psychotherapy may improve initiation and completion of CPT and PE, particularly for certain minoritized and high-risk groups.