Abstract: Introduction: Trauma-related guilt is associated with suicidality among veterans. Limited research has examined if addressing trauma-related guilt in treatment decreases suicidal ideation (SI). Investigating pathways for reducing risk factors for suicide is crucial given the high rates of veteran suicide. Method: U.S. combat veterans (N = 145) deployed in service of post-9/11 conflicts enrolled and randomized in a randomized controlled trial comparing Trauma Informed Guilt Reduction Therapy (TrIGR) with Supportive Care Therapy (SCT). This study included a subset of participants endorsing trauma-related guilt and SI at baseline (N = 73; mean age = 39, 93.2 % male). Veterans completed semi-structured interviews of suicidal thoughts and behaviors (Columbia Suicide Severity Rating Scale; C-SSRS) and a self-report measure of trauma-related guilt (Trauma Related Guilt Inventory; TRGI) at baseline, posttreatment, 3- and 6-month follow-ups. Two outcome variables were examined: SI intensity (i.e., wish to be dead to active suicidal ideation with specific plan and intent) and severity (i.e., frequency, duration, controllability, deterrents, and reasons for ideation). Linear mixed models tested whether: 1) SI intensity and severity changed significantly over time across both treatments and 2) there was a significant treatment effect on SI intensity and severity. Results: SI intensity (b = −1.17, p < 0.001) and severity (b = −0.35, p < 0.001) decreased over time in both conditions; however, significant differences between treatments were not observed. Conclusions: Supportive therapy and therapy targeting trauma-related guilt were associated with decreased SI among treatment-seeking veterans presenting with SI. Findings suggest that brief interventions can reduce SI.