Oral squamous cell carcinoma (OSCC) is the most prevalent and deadly malignancy of the head and neck. The standard treatments for OSCC are surgery, radiotherapy, and chemoradiotherapy, which can cause severe cosmetic and functional damage to the oral cavity and impair the patients' quality of life. Photodynamic therapy (PDT) is a promising alternative that uses light-activated photosensitizers to induce selective phototoxicity and necrosis in the target tissues. PDT has several advantages over conventional treatments, such as minimal invasion, low side effects, high selectivity and preservation of the oral function and appearance. This review explores the principles, mechanisms, and current applications of PDT for OSCC. We address the challenges, such as the depth of light penetration and tissue hypoxia, and underscore the progressive innovations in photosensitizer enhancement, nanotechnological integration, and precision therapy. The exploration of biomarkers for refining patient selection and tailoring individualized treatment regimens is also undertaken. PDT holds promise as a secure and efficacious modality for OSCC management. Nonetheless, additional investigation is imperative to refine treatment protocols and validate sustained therapeutic success.