<p>Taurine, a bio-based sulfur- and nitrogen-containing compound, has recently attracted attention as a sustainable flame-retardant additive for polymeric materials. However, its potential in enhancing the fire resistance of wood remains largely unexplored. In this study, the effects of taurine on the thermal degradation behavior and combustion performance of wood were systematically investigated using pyrolysis kinetics, cone calorimetry, and thermogravimetry–infrared spectroscopy (TG–FTIR). Taurine treatment promoted catalytic char formation during thermal degradation, resulting in a lower maximum degradation temperature and higher char yield. Kinetic analysis revealed that taurine-treated wood underwent three distinct decomposition stages with activation energies significantly higher than those of untreated wood, indicating an increased energy barrier for pyrolysis. Cone calorimetry results showed that taurine markedly suppressed heat release in the later stages of combustion and effectively reduced total smoke production. TG–FTIR analysis confirmed the release of sulfur- and nitrogen-containing species, which can capture free radicals, inhibit combustion chain reactions, and dilute oxygen and flammable gases, thereby enhancing flame retardancy. This work provides the first comprehensive elucidation of taurine’s flame-retardant mechanism in wood, revealing its dual condensed- and gas-phase synergistic effects and offering new insight into the development of bio-based, environmentally friendly, and efficient flame-retardant systems for wood materials.</p>