Abstract: The human microbiome consists of microbial communities inhabiting different body sites and their genetic information, and plays an important role in maintaining host health. As an important component of the human microbiome, the oral microbiota contributes to maintaining oral microbial homeostasis, regulating local immune responses, participating in nutrient metabolism, and modulating systemic health. Initial colonization of the oral microbiota in early life lays the foundation for subsequent microbial development and lifelong oral health, and alterations in the oral microbiota are closely associated with various oral and systemic diseases. This review systematically summarizes the age-related succession of the oral microbiota across infancy, childhood and adolescence, adulthood, and old age; analyzes oral diseases associated with microbial dysbiosis at different life stages; discusses host-related, microenvironmental, and exogenous factors influencing age-related changes in the oral microbiota; and summarizes intervention strategies based on microbial ecological regulation. This review aims to provide new insights into age-related changes in the oral microbiota and to support the development of a life-course oral microbial health management model.