<p>Over recent decades, the prevalence of allergic diseases has risen steadily, particularly among children, making these conditions a major global public health concern. Increasing evidence suggests that, in addition to genetic factors, gut microbiota dysbiosis is an important contributor to the development and progression of allergic diseases. The gut microbiota plays a critical role in host metabolism, maintenance of mucosal barrier integrity, and regulation of immune homeostasis, and is especially closely linked to immune system development and the establishment of immune tolerance in early life. Abnormalities in the composition and function of the gut microbiota may promote allergic susceptibility through multiple immunoregulatory pathways and contribute to the onset and progression of atopic dermatitis, allergic rhinitis, asthma, and other allergic diseases. This review focuses on the relationship between early-life gut microbiota and allergic diseases, summarizes the underlying immunoregulatory mechanisms, and discusses progress in microbiota-targeted interventions, with the aim of providing a reference for early prevention and precision intervention in allergic diseases.</p>