Abstract : Soil stabilization has become a major trend in construction engineering and the researches regarding the effectiveness of using natural fibers are rapidly increasing. The aim of present study is to stabilize soil with bottom ash (BA) and reinforcing it with sisal fiber so as to achieve maximum load bearing capacity for the soil to be used as foundation material. Several studies on use of synthetic fibers for soil stabilization are available in the literature but these fibers are much expensive and not easily available. Stabilizing agent used in this study is BA and reinforcing material used are sisal fibers. BA is formed in coal furnaces and it is a waste product. The present study investigates the strength of the soil which is modified with BA and fibers which are added at a different percentage to the soil. A series of laboratory tests were conducted on soil sample stabilized with BA and different percentages of sisal fibers. The test method includes Compaction tests and unconfined compression strength (UCS) tests. The percentage of BA is varied from 0 to 40% and for fiber it is varied from 0 to 2%. Further model footing tests were conducted in a steel tank to evaluate the settlement-bearing pressure behavior of the stabilized soil under increment loading. The performance of sisal fiber was compared with that of poly vinyl alcohol (PVA) fiber. The test results indicate the competency of sisal fiber to be used as reinforcement in soils with better performance than PVA fibers. © 2019 American Society of Civil Engineers.