This study aimed to evaluate the anthelmintic potential of aqueous and ethanoic leaf extracts of Azadirachta indica and Vitex negundo against benzimidazole-resistant Haemonchus contortus of sheep. A total of 560 dung samples collected from organized sheep farms in Salem, Karur, Kanniyakumari, Kancheepuram and Thiruvallur districts of Tamil Nadu were examined by FECRT to assess the development of resistance to benzimidazole (BZ). The samples from Kancheepuram and Thiruvallur districts showed resistance to benzimidazole by FECRT. The allele-specific PCR (AS-PCR) revealed amplification of a 250bp fragment which confirmed resistance to benzimidazole in samples from Kancheepuram and Thiruvallur districts. Aqueous leaf extracts (ALE) and Ethanolic leaf extracts (ELE) of A. indica and V. negundo at different concentrations viz., 5, 10, 20 and 50 mg/mL, were tested against resistant H. contortus of sheep reared in these farms with BZ resistance. The maximum of 35.42±1.87% inhibition of egg hatch was observed in aqueous leaf extracts (ALE) of A. indica with 50 mg/mL concentration compared to 26.67±1.23 % inhibition of egg hatch in ethanolic leaf extract (ELE). Whereas, the maximum efficacy (%) in egg hatch assay observed in ALE and ELE of V. negundo were 11.67±1.67 and 5.00±0.91, respectively in 50 mg/mL concentration. The maximum mean larval paralysis observed in ALE and ELE of A. indica were 28.89±1.11% and 26.67±1.23 % respectively in 50 mg/mL concentration at 60 min. Whereas, the maximum mean larval paralysis observed in 50 mg/mL concentrations of ALE and ELE of V. negundo were 13.44±1.41 and 7.23±0.55, respectively, at 60 min. It was observed that ALE and ELE of A. indica and V. negundo produced a dose-dependent increase in efficacy in the inhibition of egg hatch and mean larval paralysis. It is concluded that A. indica and V. negundo could be the promising phytomedicines for the alternative control strategy of benzimidazole-resistant nematodes of sheep.