Prolonged exposure therapy (PE) is a well‐established first‐line treatment for posttraumatic stress disorder (PTSD) that is based on emotional processing theory. PE has been rigorously evaluated and tested in a large number of clinical trials in many countries covering a wide range of trauma populations. In this review, we summarize the evidence base supporting the efficacy of PE across populations, including adults with sexual assault–related PTSD and mixed trauma–related PTSD, military populations, and adolescents. We highlight important strengths and gaps in the research on PE with individuals from marginalized communities. We discuss the efficacy of PE on associated psychopathology and in the presence of the most commonly comorbid conditions, either alone or integrated with other treatments. In addition, we provide an overview of research examining strategies to augment PE. Much of this work remains preliminary, but numerous trials have tested PE in combination with other psychological or pharmacological approaches, interventions to facilitate extinction learning, and behavioral approaches, in the hopes of further increasing the efficiency and efficacy of PE. There are now several trials testing PE in novel formats that may have advantages over standard in‐person PE, such as lower dropout and increased scalability. We examine this recent work on new models of delivering PE, including massed treatment, telehealth, and brief adaptations for primary care, all of which have the potential to increase access to PE. Finally, we highlight several promising areas for future research.