This systematic review and meta-analysis evaluates the reliability of salivary biomarkers for diagnosing Alzheimer's Disease (AD). The study included 30 studies from 17 countries, involving 1371 participants. The primary biomarkers examined were proteins, metabolites, and miRNAs. Meta-analysis revealed that salivary levels of beta-amyloid42 and p-tau were significantly increased in AD patients, while t-tau and lactoferrin levels were decreased at borderline statistical significance. Lactoferrin and beta-amyloid42 showed significant predictive value for AD diagnosis with AUC values of 0.896 and 0.803, respectively. The review highlights that potential markers such as beta-amyloid42, tau, and lactoferrin can be detected in saliva, supporting early diagnosis of AD. However, further research is needed to confirm these findings and explore other potential biomarkers.This systematic review and meta-analysis evaluates the reliability of salivary biomarkers for diagnosing Alzheimer's Disease (AD). The study included 30 studies from 17 countries, involving 1371 participants. The primary biomarkers examined were proteins, metabolites, and miRNAs. Meta-analysis revealed that salivary levels of beta-amyloid42 and p-tau were significantly increased in AD patients, while t-tau and lactoferrin levels were decreased at borderline statistical significance. Lactoferrin and beta-amyloid42 showed significant predictive value for AD diagnosis with AUC values of 0.896 and 0.803, respectively. The review highlights that potential markers such as beta-amyloid42, tau, and lactoferrin can be detected in saliva, supporting early diagnosis of AD. However, further research is needed to confirm these findings and explore other potential biomarkers.