Introduction: Burning mouth syndrome (BMS) is characterized by an oral burning sensation in the absence of any organic disorders of the oral cavity. Although the cause of BMS is not known, a complex association of biological and psychological factors has been identified, suggesting the existence of a multifactorial etiology. Material and Method: A PubMed/Medline search was used to identify articles describing the different hypotheses regarding the etiology of BMS, as well as the psychological and anatomical data upon which such hypotheses are fundamented. Results: A review and update was made of the different hypotheses relating to the etiology of BMS (psychogenic factors, hormone disorders, neuropathic alterations, oral phantom pain, neuroplasticity and neuroinflammation), with a view to globally establishing possible relationships among them. Conclusions: In-depth investigation is needed to clarify the etiopathogenic mechanisms of BMS and its triggering factors, in order to develop effective and individualized management strategies that can be extended to patients in each different BMS subgroup.