Abstract. The alcoholic extract of Acacia senegal is tested as corrosion inhibitor for aluminium in acid media by employing mass loss and thermometric techniques. It has been found that the extract acts as a good corrosion inhibitor for aluminium in 1N sulphuric and hydrochloric acid solution. Generally, inhibition was found to increase with increase in inhibition concentration, half-life, activation energy and decrease in the first order rate constants at 30 and 40 ⁰C. The inhibition action of the extract is also discussed in view of Langmuir adsorption isotherm. It has been observed that the adsorption of the extract on aluminium surface is a spontaneous process. The acacia extract provides a good protection to aluminium against corrosion.