Gamma radiation offers a versatile approach for the synthesis of silica-based nanomaterials, leveraging high-energy radiolysis to produce pure and finely structured composites without the need for surfactants or capping agents. This review explores the underlying mechanisms of γ-ray-induced radiolytic reduction, detailing the interaction of radiolytic species with silica matrices to synthesize metallic and hybrid nanomaterials. Emphasis is placed on the synthesis of silver and noble metal composites, which demonstrate promising properties for catalytic, antimicrobial, and sensing applications. The influence of synthesis parameters, such as dose, pH, and matrix characteristics, on nanoparticle size and yield is discussed. Emerging applications of these materials in biomedical devices and environmental technologies are presented. While γ-ray synthesis circumvents issues of contamination and scalability inherent in chemical methods, challenges such as accessibility to radiation sources and control over nanoparticle morphology remain. Future research directions are proposed, including the extension of this technique to multimetallic systems, sulfide-based nanocomposites, and hybrid materials.