Mindfulness-based interventions (MBIs), with postures, breath, relaxation, and meditation, such as Mindfulness-based Stress Reduction (MBSR) and yoga, are complex interventions increasingly used for trauma-related psychiatric conditions. Prior reviews have adopted a disorder-specific focus. However, trauma is a risk factor for most psychiatric conditions. We adopted a transdiagnostic approach to evaluate the efficacy of MBIs for the consequences of trauma, agnostic to diagnosis. AMED, CINAHL, Central, Embase, Pubmed/Medline, PsycINFO, and Scopus were searched to 30 September 2018 for controlled and uncontrolled trials of mindfulness, yoga, tai chi, and qi gong in people specifically selected for trauma exposure. Of >12,000 results, 66 studies were included in the systematic review and 24 controlled studies were meta-analyzed. There was a significant, pooled effect of MBIs (g = 0.51, 95%CI 0.31 to 0.71, p < .001). Similar effects were observed for mindfulness (g = 0.45, 0.26 to 0.64, p < .001), yoga (g = 0.46, 0.26 to 0.66, p < .001), and integrative exercise (g = 0.94, 0.37 to 1.51, p = .001), with no difference between interventions. Outcome measure or trauma type did not influence the effectiveness, but interventions of 8 weeks or more were more effective than shorter interventions (Q = 8.39, df = 2, p = .02). Mindfulness-based interventions, adjunctive to treatment-as-usual of medication and/or psychotherapy, are effective in reducing trauma-related symptoms. Yoga and mindfulness have comparable effectiveness. Many psychiatric studies do not report trauma exposure, focusing on disorder-specific outcomes, but this review suggests a transdiagnostic approach could be adopted in the treatment of trauma sequelae with MBIs. More rigorous reporting of trauma exposure and MBI treatment protocols is recommended to enhance future research.