Eye movement desensitisation and reprocessing (EMDR) is an established psychotherapy developed in the late 1980s to treat post-traumatic stress disorder (PTSD). It involves the use of repetitive eye movements or other bilateral stimulation to aid in the reprocessing of traumatic memories. It is unique in that it does not require extended exposure to or discussion of distressing memories and may result in symptom resolution in fewer sessions than other psychotherapies. In the decades since its initial development, a wealth of high-quality evidence has suggested that EMDR is a safe and effective treatment for trauma- and stress-based conditions, resulting in its inclusion in various treatment guidelines. This article reviews the theory behind how EMDR works, how it is conducted, the evidence supporting its use in the treatment of PTSD and its approved indications and contraindications.