The effect of aqueous extract of adathoda vasica leaves (AVL) on corrosion inhibition of aluminium in 1N NaOH solution was studied using chemical and electrochemical techniques. It was found that the inhibition efficiency increased with the increase of adathoda vasica extract upto 800 ppm. Beyond this concentration there is no improvement in the inhibition efficiency. Electrochemical measurements revealed that AVL extract acts as a mixed type inhibitor. Adsorption of AVL extract was found to follow Langmuir adsorption isotherm. The results obtained from chemical and electrochemical measurements are in reasonably good agreement. The protective film formed on the surface of aluminium by the adsorption of water-soluble chemical constituents of AVL extract was confirmed using scanning electron microscopy studies.