Saliva has emerged as a promising diagnostic fluid due to its non-invasive collection, ease of handling, and rich composition of biological molecules. Salivary biomarkers offer significant potential for the early detection, diagnosis, prognosis, and monitoring of various oral diseases, including dental caries, periodontal disease, oral potentially malignant disorders, and oral squamous cell carcinoma. Recent advances in molecular biology, proteomics, genomics, transcriptomics, and metabolomics have enhanced the identification and validation of salivary biomarkers for clinical applications. This review explores the role of salivary biomarkers in oral disease diagnosis, discusses current diagnostic technologies, evaluates their clinical utility, and highlights future prospects in precision dentistry. The study concludes that salivary diagnostics may revolutionize oral healthcare by enabling rapid, accurate, and personalized disease management.