Testimony therapy can provide low-cost, brief, simple, and culturally adaptable psychosocial services in low-income countries (Agger, Raghuvanshi, Khan, Polatin, & Laursen, 2009). Nonetheless, there have been no well-controlled studies of testimony therapy. We report the analyses of a randomized controlled trial designed to assess the effectiveness of testimony therapy plus a culturally adapted ceremony in reducing mental health symptoms among Khmer Rouge torture survivors from across Cambodia. Using multilevel modeling, we compared symptoms of posttraumatic stress disorder, anxiety, and depression between a treatment (n = 45) and a control group (n = 43) at baseline, 3 months, and 6 months. We found that testimony therapy plus ceremony significantly reduced symptoms of posttraumatic stress disorder (d = 0.49), anxiety (d = 0.44), and depression (d = 0.53).