Objective: This individual participant data meta-analysis aimed to investigate the effectiveness of cognitive behavioral therapy with a trauma focus (CBT-TF) for posttraumatic stress disorder (PTSD). Furthermore, we examined the effect of moderators on PTSD symptom severity. Method: This study included randomized controlled trials comparing CBT-TF to an inactive or active comparison group for adults with PTSD. The primary and secondary outcomes were PTSD symptom severity and remission, respectively. Moderators included sociodemographic and clinical variables. Results: Twelve studies compared CBT-TF with inactive (n = 625) and 11 with active comparison conditions (n = 706). The one-stage individual participant data meta-analysis found that CBT-TF was more effective than inactive comparison conditions (beta = -0.78; OR = 2.34) and not significantly different from active comparison conditions (beta = 0.02; OR = 0.53) in reducing PTSD symptom severity and achieving PTSD remission, respectively. When comparing CBT-TF with inactive treatments, moderator analysis found that divorced participants had greater PTSD symptoms postintervention following CBT-TF than participants who were single, cohabitating, or married receiving CBT-TF, both in the completer (beta = 0.93) and full-sample (beta = 0.59) analyses. For the active treatment comparison, moderator analysis found that participants taking psychotropic medication had lower PTSD symptoms following CBT-TF than those not taking psychotropic medication in the completer analysis (beta = -0.39). Conclusion: Based on our moderator analyses, further research is needed to understand the effect of psychotropic medication on the CBT-TF intervention process. Moreover, divorced participants with PTSD receiving CBT-TF might benefit from enhanced support.