Background <p>Oral lichen planus (OLP) is a chronic immune-mediated disease affecting the mucous membranes of the oral cavity, regarded as a potentially malignant disorder.</p> Methods <p>We performed a narrative review of the literature compiling key hypotheses on the etiopathogenesis of OLP, addressing recently raised aspects and questions yet to be elucidated.</p> Results <p>The etiopathogenesis of OLP is complex and not fully understood, with evidence suggesting a multifactorial cause. Lesions appear to be triggered by the recognition of one or more antigens, provoking a dysregulated T-cell-mediated immune response against oral keratinocytes. Genetic and environmental factors significantly influence the orchestration of various immune and non-immune cells, cytokines, and molecules involved in this pathological process.</p> Conclusions <p>Understanding recent theories on the etiopathogenesis of OLP is crucial forguiding future research on its diagnosis and treatment, as well as on preventing its malignant transformation.</p>