Abstract: Preliminary studies have demonstrated the efficacy of Transcendental Meditation (TM) for treating posttraumatic stress disorder (PTSD). The present study extended previous research with a pilot trial of TM as a treatment for PTSD via a single-blinded, randomized controlled design. veterans with PTSD (N = 40) were assigned to a TM intervention or treatment-as-usual (TAU) control group. Participants in the TM group engaged in 16 sessions over 12 weeks, primarily in a 60-min group format. Change in PTSD symptoms, measured via the Clinician-Administered PTSD Scale for DSM-5 (CAPS-5) was the primary outcome. Secondary outcomes included self-reported PTSD symptoms, depression, anxiety, sleep difficulties, anger, and quality of life (QoL). Assessments were conducted at baseline and 3-month follow-up. Mean CAPS-5 score decreases were significantly larger for participants in the TM group (M = -11.28, 95% CI [-17.35, -5.20]), compared to the TAU group (M = −1.62, 95% CI [-6.77, 3.52]), p = .012, d = -0.84. At posttest, 50.0% of veterans in the TM group no longer met PTSD diagnostic criteria as compared to 10.0% in the TAU group, p = .007. Adjusted mean changes on self-report measures of PTSD symptoms, depression, anxiety, and sleep difficulties indicated significant reductions in the TM group compared to TAU, ds = .80–1.16. There were no significant group differences regarding anger or QoL. These findings demonstrate the efficacy of TM as a treatment for veterans with PTSD and for comorbid symptoms. Combined with other research, they suggest that TM may be a tolerable, non–trauma-focused PTSD treatment.