Posttraumatic stress disorder (PTSD) is associated with high morbidity and functional impairment in the absence of effective treatment. Exposure therapy for PTSD is a trauma-focused treatment that typically includes in vivo and/or imaginal exposure. The goal of this meta-analysis was to examine the overall efficacy of exposure therapy for PTSD compared to various control conditions. We also assessed the efficacy of individual exposure-based treatments and the potentially moderating impact of various demographic, clinical, and treatment-related factors. PsycINFO and Medline were searched for randomized controlled trials of exposure-based therapies for adult PTSD. A total of 934 abstracts were screened for initial eligibility; of these, 65 articles met inclusion criteria and were included in the meta-analysis (total N = 4929 patients). Exposure therapy showed large effects relative to waitlist and treatment-as-usual, a small effect relative to non-trauma-focused comparators and a negligible effect relative to other trauma-focused treatments or medication. At follow-up most effects sizes were stable, except for a medium effect favoring exposure over medication. The individual exposure-based therapies examined were similarly effective. Moderator analyses revealed larger effect sizes in studies with fewer sessions, younger samples, fewer participants diagnosed with substance use disorder, and fewer participants on psychiatric medication. Effect sizes were also larger in studies of refugees and civilians compared to military samples, studies of PTSD related to natural disasters and transportation accidents vs. other traumatic events, and studies of individual vs. group therapy. Findings support the overall efficacy of exposure therapy and highlight that there are a number of efficacious exposure-based therapies available.