This systematic review and meta-analysis evaluated the reliability of salivary biomarkers for diagnosing Alzheimer's Disease (AD). Thirty studies were included, focusing on proteins, metabolites, and miRNAs. Meta-analysis revealed significant increases in salivary beta-amyloid42 and p-tau levels in AD patients, while t-tau and lactoferrin levels were decreased. Pooled AUC analysis showed lactoferrin and beta-amyloid42 had significant predictive value for AD diagnosis. Potential markers such as beta-amyloid42, tau, and lactoferrin could be detected in AD saliva, supporting early diagnosis. However, study limitations included heterogeneity in diagnostic methods and biomarker diversity, making comparisons challenging. Further research is needed to confirm findings and explore other substances' predictive abilities. The review highlights the potential of salivary biomarkers in AD diagnosis, though validation is required.This systematic review and meta-analysis evaluated the reliability of salivary biomarkers for diagnosing Alzheimer's Disease (AD). Thirty studies were included, focusing on proteins, metabolites, and miRNAs. Meta-analysis revealed significant increases in salivary beta-amyloid42 and p-tau levels in AD patients, while t-tau and lactoferrin levels were decreased. Pooled AUC analysis showed lactoferrin and beta-amyloid42 had significant predictive value for AD diagnosis. Potential markers such as beta-amyloid42, tau, and lactoferrin could be detected in AD saliva, supporting early diagnosis. However, study limitations included heterogeneity in diagnostic methods and biomarker diversity, making comparisons challenging. Further research is needed to confirm findings and explore other substances' predictive abilities. The review highlights the potential of salivary biomarkers in AD diagnosis, though validation is required.