The worldwide problem of expansive soils is a threat to civil engineers. They are considered a potential natural hazard, which can cause extensive damage to structures if not adequately treated. Such soils swell when given an access to water and shrink when they dry out. Soil stabilization has been implemented for improving the properties of these soils. Since the volume of wastes generated in the world has increased over the years due to increase in population, socioeconomic activities and social development hence utilization of these waste materials in the improvement of soils is a cost efficient and environmental friendly method. In this paper, coconut husk ash (CHA) is used as a stabilizer to improve the properties of expansive clayey soils. Various engineering tests like Unconfined Compressive Strength (UCS), California Bearing Ration (CBR), Proctor Test, Free Swell Index Test (FSI) were performed at varying percentage of CHA (2, 4, 6, 8, 10) and at varying curing periods (2 days, 4 days and 7 days) to find the optimum range of CHA to use as stabilizer. It is found that with the increase in the percentage of CHA the UCS and CBR values increases upto 8% at a curing period of 7 days. It is finally concluded that the optimum range for percentage of CHA to be used as soil stabilizer is found to be 8%. Keywords- Expansive Soil, Soil Stabilization, Coconut husk ash, Environment friendly, Curing Periods