Corrosion inhibition effects of Ocimum Sanctum extract on aluminium in HCl were studied by weight loss, Potentiodynamic polarization method and AC impedance. Spectral studies such as FT-IR, UV studies show functional groups present in Ocimum Sanctum. The worn surfaces of aluminum plates were observed using scanning electron microscope (SEM). The maximum inhibition efficiency of weight loss method and polarization method are 97% and 88.22% in 2 hours at room temperature. The maximum inhibition efficiency obtained from the impedance method was at 298K in the extract concentration of 0.1%. The inhibition efficiency obtained by the weight loss method was in good agreement with polarization and impedance methods. The results show that Ocimum Sanctum extract is an effective green inhibitor.