This paper presents the shear strength of stabilized expansive clay using coconut shell ash in varying proportions from 2 to 8% of dry weight of the soils. To achieve this objective, laboratory investigations such as index and engineering properties tests were conducted for the stabilized and unstabilized expansive clayey soil. It is indicating from the laboratory result that by addition of coconut shell ash to expansive clay soil has shown a reduction in swelling and a significant improvement in shear strength as compared to unstabilized natural expansive clay soil. In general, the shear strength of stabilized expansive clay is increasing with increase in percentage of coconut shell ash. Also, there is an improvement in plastic characteristics of stabilized expansive clay using coconut shell ash. The optimum percentage of coconut shell ash content in terms of strength criteria is found to 6%.