Oral cancer is the sixth most common cancer globally, where almost one-third of the total burden is contributed by India, thus ranking second in having the highest number of oral cancer cases. Most of the oral cancer patients do not show early symptoms with diagnosis being done at advanced stage of the disease, contributing to a low 5-year survival rate. Early detection may be imperative to reduce mortality in oral cancer. Hence, there is a need to employ a cost-effective and non-invasive technique to diagnose and differentiate these malignancies at various stages. Optical Spectrometry may provide a solution appropriate to facilitate the above due to its advantages over traditional methods such as painlessness, speed, sensitivity, objectivity, cost, and ease-of use in clinical setting. This review aims to provide a comprehensive overview of optical spectrometry in biological fluids and tissues for oral precancer and cancer diagnosis. A literature review was carried out in PubMed database, using keywords "Optical Spectroscopy", “Oral precancer” “Oral Cancer” and “Early Detection”. Research and review articles dealing with diagnosis of oral cancer using optical spectroscopy were considered and summarised according to the Year, technique used, their sensitivities and specificities.