In this study, the diffusion and sorption behavior of glycidyl methacrylate in styrene butadiene rubber (SBR) was investigated as a function of waste tire powder content, sulfur content (i.e., the crosslink density), and temperature by using the gravimetric sorption method. The results indicate that penetrant solubility increases as sulfur and waste tire powder contents decrease, whereas the temperature affects the solubility favorably. The results also indicate that mutual diffusion coefficients decrease as the sulfur and waste tire powder contents increase. This behavior was interpreted in terms of free volume of the polymer and tortuosity.