<p>The escalating levels of environmental pollution, driven by industrial activities and urban expansion, pose a significant threat to global health and ecological balance. In response to this pressing challenge, the oxidation of pollutants has emerged as a crucial strategy for environmental remediation. This process involves transforming harmful substances into less toxic or benign products, often through reactions with oxidizing agents. Catalytic oxidation, in particular, offers a promising approach, enabling efficient and selective pollutant removal under relatively mild conditions. Developing effective catalysts is therefore paramount in the pursuit of cleaner air. This review critically examines various Ag-based catalytic systems, including supported Ag catalysts, Ag-doped oxides, bimetallic systems (e.g., Au-Ag), silver nanoclusters and single-atom catalysts for CO oxidation activity. Key strategies to enhance catalytic performance—such as tuning silver dispersion, modifying oxidation states, and employing diverse supports like silica, SBA-15, and activated carbon—are highlighted. The effect of pre-treatment conditions and the nature of oxygen species (surface vs. subsurface) are the critical factors that affect the CO oxidation activity. Mechanistic insights reveal that both Langmuir-Hinshelwood and Eley-Rideal pathways are operative, depending on catalyst composition, silver species (Ag⁺ or Ag⁰), and reaction conditions. Additionally, the review underscores the structure-sensitive nature of the reaction and the critical role of coordinatively unsaturated Ag atoms.</p>