This paper evaluates the effectiveness of stabilizing expansive soil with two different types of fibers, Fiber Mesh® (FM) and Fiber Cast® (FC), in conjunction with chemical stabilization. The intention of this study is to evaluate the effect of these fibers and lime in stabilizing expansive soil by improving its UCS behavior. The effect of varying lengths (6 mm and 12 mm) and amounts (0.2, 0.4 and 0.6% dosage by weight of soil) of FC and FM fibers and curing periods (0, 7, 28, 60, 120, 180 and 360 days) on the UCS and on secant modulus of a semi-arid expansive soil, in the presence of lime, was investigated. The main focus of this paper is on the determination of optimum fiber reinforcement parameters (in terms of fiber type, length and dosage) for the stabilization of expansive soil in terms of UCS, which is of a prime importance in soil stabilization projects for practicing engineers. In deterministic optimization, the uncertainties associated with subgrade soil of the pavement system are not explicitly taken into account. Hence, resulting optimal solutions may lead to reduced reliability levels of the pavement. Therefore, this paper also focuses on determining the optimum amounts of reinforcement for desired UCS performance of lime blended expansive soil using target reliability approach (TRA). The experimental data was used to develop a parabolic model using factors such as, length and dosage of fiber types to predict UCS as a response variable. In addition, it was concluded that the TRA can be successfully employed in expansive soil stabilization applications in determining the optimum length and dosage of fiber reinforcements.