This document summarizes research on stabilizing soil using coconut coir fiber. Laboratory tests were conducted on soil samples with 0-3% coconut coir fiber additions to evaluate properties like California Bearing Ratio, Unconfined Compressive Strength, Optimum Moisture Content, and Maximum Dry Density. Results showed that engineering properties like strength and bearing capacity improved with coconut coir fiber content up to 1%. Coconut coir fiber is a low-cost agricultural waste that can effectively stabilize weak soils and improve their engineering performance for construction applications.