Introduction Peroral endoscopic myotomy (POEM) is a novel intervention for the treatment of achalasia, which combines the advantages of endoscopic access and myotomy. The purpose of this study was to perform a systematic review of the literature to evaluate the efficacy and safety of POEM. Methods The systematic review was conducted following the PRISMA guidelines. Evidence-Based Medicine Reviews, Cochrane Central Register of Controlled Trials, Ovid MEDLINE (R) including in-process and non-indexed citations were searched for POEM studies using the keywords: esophageal achalasia, POEM, endoscopy, natural orifice surgery, laparoscopic Heller myotomy (LHM), and related terms. Eckardt score, lower esophageal sphincter (LES) pressure, and reported complications were the main outcomes. Two authors reviewed the search result independently. A third reviewer resolved all disagreements. Data abstraction was pilot-tested and approved by all authors. Data were examined for clinical, methodological, and statistical heterogeneity with the aim of determining whether evidence synthesis using meta- analysis was possible. Results The search strategy retrieved 2894 citations. After removing duplicates and applying the exclusion criteria, 54 studies were selected for full-text review of which a total of 19 studies were considered eligible for further analysis. There were 10 retrospective and 9 prospective studies, including 1299 POEM procedures. No randomized control trial (RCT) was identified. Overall, the pre- and post-POEM Eckardt scores and LES pressure were significantly different. The most frequently reported complications were mucosal perforation, subcutaneous emphysema, pneumoperitoneum, pneumothorax, pneumomediastinum, pleural effusion, and pneumonia. The median follow-up was 13 months (range 3–24). Conclusion POEM is a safe and effective alternative for the treatment of achalasia. However, only short-term follow-up data compared with LHM are available. RCTs and long-term follow-up studies are needed to establish the efficacy and safety of POEM in the management of patients with achalasia.