The existence of uncertainty in the design parameters of anchored rock slopes warrants reliability based study. An approach for reliability based design optimization of anchored rock slopes against plane failure is described under different hydraulic distributions. Planar slide failure along with water pressure has been considered in conjunction with Barton-Bandis failure criterion to compute the factor of safety. Nonlinear strength criterion is employed for the computation of strength of jointed rock mass. The rock bolt and rock mass interaction model is used to analyze the stabilizing force in anchors. The variability associated with Barton-Bandis parameters, namely joint compressive strength (JCS), joint roughness coefficient (JRC), and basic friction angle (ψ) and a joint factor is considered. The target reliability based design optimization (TRBDO) is used to obtain an optimum length of the rock bolt and optimum anchor force required to stabilize the rock slope in order that the reliability index must meet a desired level of safety. © 2020 American Society of Civil Engineers.