Supermarkets and commercial center stores need to reduce operational costs due to increasing competition. Big-box retail stores in USA potentially can reduce its energy consumption up to 30%. Several studies have shown that living walls and vegetative roofs are able to reduce building energy consumption especially in hot and warm climates. Big-box retail stores have large opaque surfaces than can be used to install such technologies. However, there is a lack of studies evaluating the impacts of living walls and green roofs on the thermal and energy performance of retail buildings. For this reason, this paper aims to compare the effect of green roofs and living walls on the energy consumption of a retail prototype building located in Santiago of Chile, which is characterized by a semiarid climate (Bsk according to Köppen-Geiger climate classification). Two validated green roof heat and mass transfer (GRHMT) models are adapted for living walls (LWHMT models). The validation of the GRHMT models was previously done for different climates represented by the cities of Santiago (Chile), Melbourne (Australia) and Chicago (USA), while the adapted LWHMT models is validated for Santiago (Chile) in this paper. The validation shows very good agreement between the experimental and simulation data for foliage and substrate temperatures. GRHMT and LWHMT models are coupled to EnergyPlus® through MLE+®, an open-source MATLAB Simulink toolbox for co-simulation with EnergyPlus. Finally, the thermal performance of an ASHRAE prototype retail building is carried out for the base case, green roof only, living walls only and combination of a green roof and living walls. Comparing the impact of the living walls and green roof, results show a better performance of living walls, reducing the annual thermal loads by 23.2% in comparison with the reduction of 16.4% provided by the green roof system. Reduction in thermal loads are mostly cooling loads due to the shading and evapotranspiration effects of vegetative covers, which cool the building surfaces. Furthermore, the combined behavior of both systems shows an important reduction of 34.6% of annual thermal loads compared with the base case.