Introduction: recent years have witnessed a demand for ever shorter treatments in orthodontics. Treatment duration depends on diagnosis, case complexity, treatment plan, equipment, clinical experience and patient cooperation, among other factors, and generally ranges between 24 and 36 months. Some studies support the idea that low-level laser speeds up orthodontic movement; however, the photobiomodulation mechanisms involved are clear. Objective: describe the evidence of low-level laser photobiomodulation in orthodontic movement and its mechanisms. Methods: a bibliographic review was conducted in MEDLINE, PubMed and SciELO about the relationship between low-level laser photobiomodulation in orthodontic movement and its mechanisms. The search was aimed at papers published in any language mainly in the last five years. The topics consulted in the review had to do with experiments on humans, animals and in vitro in which infrared lasers (780-820 nm) were used, since infrared absorption of hemoglobin is lower than that of visible red. Infrared lasers (780-820 nm) are the best to stimulate bone cells, because their wavelengths go deeper into soft tissue, reaching the bone. Results: details are provided about photobiomodulation and the modular bases of the use of this technique in orthodontics. Low-level laser speeds up orthodontic movement; however, a specific therapeutic window has not been determined for its dosimetry and mechanism of action in individual cell types. Conclusions: evidence suggests that low-level laser speeds up orthodontic movement. Clinical evidence is still insufficient about the cellular mechanisms involved in orthodontic movement when laser radiation is used.