This study aimed to investigate the effect of soy lecithin (SL) or soy lecithin nanoparticles (nano-SL) together with green tea extract (GTE) on the frozen-thawed buffalo bull semen quality through its incorporation in the extended semen before cryopreservation. Semen was collected once weekly for six consecutive weeks from twelve Egyptian buffalo bulls of proven fertility (n= 72 samples), using a bovine artificial vagina. Semen was divided into 3 aliquots, each was extended with one of three extenders: Extender 1 (20% egg yolk-Tris), Extender 2 (4% SL+ 0.75% GTE-Tris), and Extender 3 (2% nano-SL+0.75% GTE-Tris), before cooling, equilibration, and freezing procedures. The frozen-thawed semen was assessed for motility and kinematics, acrosomal intactness, plasma membrane and DNA integrities, and antioxidant properties. The results showed that extender 2 and 3 considerably (P< 0.0001) improved sperm motility (total and progressive motilities), DNA intactness, and improved the semen antioxidant properties (increase the total antioxidant capacity, superoxide dismutase, catalase, reduced glutathione activities, and decreased malondialdehyde levels). In conclusion, the incorporation of soy lecithin or soy lecithin nanoparticles together with green tea extract in semen extenders improved the frozen-thawed buffalo bull semen quality.