The inhibition efficacy of Emblica officinalis leaves extract on the corrosion of Copper and its alloy (Cu-27Zn) in Natural sea water environment has been studied by mass loss measurements at various time and temperature. The inhibition efficiency is markedly higher in Natural sea water environment with addition of Emblica officinalis leaves extract compared with those in the inhibitor free solution. The inhibition efficiency increased with increase of inhibitor concentration but decreased with rise in temperature and time. Corrosion inhibition may be due to the spontaneous physical adsorption of the plant constituents on the surface of Copper and its alloy. Experimental data fitted the Langmuir and Temkin adsorption isotherms. On comparing the UV and IR spectrum of alcoholic crystals of inhibitor and the corrosion product on Copper in the presence of inhibitor is reported.