The S-Scheme heterojunction design offers a promising pathway to enhance the photocatalytic activity of semiconductors for antibiotic degradation in aquatic environments. Graphitic carbon nitride (g-CN) stands out due to its robust visible light absorption, exceptional charge separation efficiency, and abundant active sites, rendering it an ideal candidate for sustainable and energy-efficient photocatalysis. This review delves into the potential of g-CN-based S-Scheme heterojunctions in antibiotic degradation, with a particular emphasis on the photocatalytic principles, inherent advantages, and application prospects. We discuss various semiconductor materials, including metal oxides, multicomponent metal oxides, magnetic oxides, multicomponent magnetic oxides, metal sulfides, and multicomponent metal sulfides, which can be paired with g-CN to fabricate S-Scheme heterojunctions. Furthermore, we explore common preparation techniques for synthesizing g-CN-based S-Scheme heterojunction composites, such as the hydrothermal method, solvothermal method, calcination method, self-assembly method, in situ growth, etc. Additionally, we summarize the applications of these g-CN-based S-Scheme heterojunctions in the degradation of antibiotics, focusing specifically on quinolones and tetracyclines. By providing insights into the development of these heterojunctions, we actively contribute to the ongoing exploration of innovative technologies in the field of photocatalytic antibiotic degradation. Our findings underscore the vast potential of g-CN-based S-Scheme heterojunctions in addressing the challenge of antibiotic contamination in water sources.