Due to the strengths of porous double skin faade (porous DSF) systems in building energy efficiency and architectural aesthetics, they have become increasingly popular in the architectural and engineering fields. Given the fact that porous DSF can soften the flow separation around building corners, it is expected that porous DSF systems should have the potential in controlling wind-induced structural responses. Therefore, a detailed wind tunnel study was conducted to investigate the effects of porous DSF on the wind-induced accelerations and structural wind loads of a typical square tall building, focusing on the influence of the porous DSF coverage area and its location. The performance of the porous DSF under different terrain conditions was also examined during the wind tunnel tests. Research results confirmed the effectiveness of the porous DSF in suppressing the across-wind responses of buildings, especially when the porous DSF located in the upper part of the building and covered at least 1/6 of the total height. It was also found that the effectiveness of the porous DSF varied with reduced wind velocity (a non-dimensional parameter). When the reduced wind velocity was lower than 10.5, the porous DSF system covering the upper 1/3 of the building height could reduce the building acceleration by 20% to 30%. When the reduced wind velocity was higher than 10.5, the building acceleration and structural wind loads could both be reduced by up to 45%. It suggests that porous DSF can not only be utilized to reduce the structural design wind loads in extreme wind events, but also be employed to improve the serviceability performance of the building in normal wind conditions. The wind tunnel tests for different terrain conditions revealed similar effects of porous DSF in reducing across-wind responses. Thus, porous DSF systems can be regarded as an ideal supplement to the existing aerodynamic approaches in building optimization design.