Background: Oral and pharyngeal cancer is the sixth most common cancer in the world. Tumoral biomarkers are important for the early diagnosis of oral cancer and to establish prognostic criteria for these lesions. Aim: The aim of this study is to assess the possible influence of salivary biomarkers on potentially malignant and malignant oral lesions. Methodology: A PubMed search through April 2018, using the following Medical Subjects Headings terms, was performed: "Mouth neoplasms," "biomarkers," and "saliva." Studies with findings on several salivary biomarkers on potentially malignant and malignant oral lesions were comprised. A total of 180 articles (156 of them fulltext articles) were found. 142 articles were excluded for several reasons: Different measurement units/detection methods (95), studies with no usable data (34), studies with no oral cancer patients group (7), and studies about malignant salivary gland tumors (6). For continuous outcomes, the estimates of effects of an intervention were expressed as mean differences (MD) using the inverse variance method together with 95% confidence intervals. Results: Fourteen studies on salivary biomarkers on potentially malignant and malignant oral lesions were included in this meta-analysis. Biomarkers with significant diagnostic and prognostic relevance in oral cancer were as follows: Interleukin 8 (IL-8) (P < 0.001), endothelin 1 (P < 0.001), IL-6 (P < 0.001), cytokeratin fraction 21-1 (P < 0.001), and carcinoembryonic antigen (P = 0.01). Conclusion: Salivary biomarkers have a important relevance in oral cancer. In the case of potentially malignant oral disorders, their relevance seems less evident. Clinical Significance: Saliva is an useful fluid to identify possible diagnostic and prognostic biomarkers in oral cancer.