This study examines the performance of an integrated evaporatively cooled-window with a desiccant dehumidification wheel combined with a photovoltaic/thermal (PV/t) system. The hybrid system is applied on a glazed building surface to reduce its temperature and reduce associated space cooling load in hot humid climate. A mathematical model of the integrated system is developed combining validated models of the PV/t, desiccant dehumidification and sensible wheel, evaporative cooler, glazing section, and an office space in order to study its performance in hot-humid climate. The integrated system model was applied during the humid month of September to a case study of a typical office space located in Jeddah, KSA having dimensions 6m×5m×3m to analyze the system effectiveness in reducing the window temperature, the space load and radiation asymmetry, while maintaining the indoor air temperature at 22ºC. Results have shown that the system was capable of performing effectively in humid climate where it reduced the space cooling load by 11% for an office having 40% window to wall ratio, compared to less than 1% when dehumidification system was not applied.