The aim of this work was to develop sustainable composites based on natural rubber (NR) and tea waste (TW) composites. The main concern was the compatibility mismatch between NR and TW. The presence of polar groups in the TW contributes to the weak interaction between relatively hydrophobic NR and TW. Therefore, silane coupling agent was introduced to enhance the properties of the composites. Treating the TW by silane coupling agent greatly influenced the overall properties of the composites. It speeded up the curing process due to its ability to reduce possible adsorption of accelerator by TW. Better interaction between TW and rubber matrix was clearly observed as evidenced by the maximum torque (MH) and tensile properties of the composites. Such findings can be verified by the Qf/Qg values, indicating better rubber-filler interaction when silane was used. Moreover, scanning electron microscope (SEM) images also provided some evidence related to the tensile properties observed. It can be concluded that the new composite based on NR and TW was successfully prepared with the contribution of a silane coupling agent.