Background: Obesity and type 2 diabetes mellitus (T2DM) are associated with chronic inflammation, immune dysfunction, and as a result increased risk of infections. Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) have emerged as key therapeutic agents with potential pleiotropic effects beyond glycemic control. Objective: This narrative review summarizes current evidence on the role of GLP-1 receptor agonists in modulating the immune–microbiome–infection axis and their potential impact on infection risk. Methods: A narrative review of recent experimental, clinical, and meta-analytic studies was performed focusing on immune regulation, inflammatory biomarkers, gut microbiota, and infectious outcomes. Results: GLP-1 RAs are associated with reduced systemic inflammation and oxidative stress, along with immunomodulatory effects including macrophage polarization and cytokine regulation. Emerging evidence suggests beneficial modulation of gut microbiota composition and improved intestinal barrier function. Studies have shown a reduction in infections, especially respiratory and systemic infections. Conclusion: GLP-1 receptor agonists may act as immunometabolic modulators linking metabolic health with immune and microbial homeostasis. Further mechanistic studies are required to clarify their role in infection susceptibility.