In a conventional side-lit room, light levels decrease rapidly as room gets deeper, resulting in excessive daylight exposure near the perimeter zones and need for artificial lighting at the back of the room. Therefore, it is not possible to achieve good lighting performance throughout the room unless any daylight strategy is developed. Advanced daylighting systems are developed to figure out this problem. Prismatic daylight-redirecting panels, for instance, improve daylight distribution through sun shading and redirection. This study mainly focuses on the performance of daylight redirecting prismatic panels attached in a south-facing, side-lit room with different room depths and windowto- wall-ratios (WWR). A deep-plan classroom was chosen as a reference case. The methodology is based on simulating the base model in Relux and testing it with alternative models composed of incrementally defined WWR and room depth values. The on-site measurements were performed to evaluate current daylight conditions and validate the simulation model. Illuminance values obtained throughout the room were evaluated in terms of the latest daylighting metrics and visual performance recommendations. Furthermore, simulation findings were used as inputs in constructing a multiple regression model to analyse the relation between room depth, window-towall- ratio and daylight illuminance. The study presents the optimal window-to-wall ratios in relation with varying room depths when prismatic panels are attached. It is considered that the requirements mentioned in standards can be revised taking account of advanced daylighting systems. Besides, the prediction model estimating illuminance in such design alternatives would be integrated in the initial design phase.