The corrosion inhibitory behaviour of Nymphae Pubescens (water lily) leaf extract (NLE) was studied using weight loss technique. NLE concentrations of 1%, 2%, 3%, 4% and 5% v/v were used at temperatures 303, 313, 323 and 333K. Functional groups present in NLE, probably responsible for the inhibition were analyzed using FTIR. Inhibition efficiency was found to increase with increasing inhibitor concentration. Temperature affected the corrosion inhibition of mild steel by NLE as corrosion rate increased with increase in temperature and a subsequent decrease in the inhibition efficiency. The highest inhibition efficiency of 85.91 % was obtained at 303K with inhibitor concentration 5%v/v and the least inhibition efficiency of 24.51% at 333K with inhibitor concentration 1%v/v. Even at 313K the highest concentration of NLE (5% v/v) gave inhibition efficiency of 77.36%. The surface morphology from scan electron microscopy examination (SEM) confirms this trend. The adsorption of the inhibitor was more suited with the Temkin adsorption isotherm and thermodynamic data calculated are suggestive of physical adsorption of the inhibitor molecules on the mild steel surface.