<p>Garlic (<i>Allium sativum</i>) is a plant rich in sulfur-containing compounds, which are the primary sources of its bioactivity and medicinal value. Studies have shown that sulfur-containing compounds in garlic, such as allicin, sulfides, and polysulfides, exhibit various physiological activities, including antioxidant, anti-inflammatory, antimicrobial, and anticancer effects. However, the content and composition of these compounds are significantly influenced by processing methods. Although extensive research has been conducted on the chemical composition and bioactivity of garlic, systematic reviews on the impact of different processing methods (heat, ageing, drying, ultrasound, high pressure, etc.) on sulfur-containing compounds and their mechanisms remain limited. This review summarizes the dynamic changes in sulfur-containing compounds during garlic processing, with a focus on the effects of processing conditions on the generation, stability, and bioavailability of these compounds. This review demonstrates that processing techniques significantly influence the stability and bioactivity of garlic sulfur compounds. Non-thermal methods such as high-pressure processing and ultrasound emerge as promising strategies for minimizing the degradation of allicin and other volatile compounds. Additionally, the impact of processing on the physiological activities of garlic’s sulfur-containing compounds is discussed, and future research directions are proposed to provide a theoretical basis for optimizing garlic processing techniques and developing functional products.</p>