This article compares daylighting in administrative building located in different climatic zones - Sweden, Czech Republic and Greece. Theese locations were chosen to best demonstrate the different lighting conditions across Europe. One room was selected and modelled, for which the daylighting in each country was then simulated and calculated. The values of the daylight factor were observed for simultaneous identical changes in window geometry and wall reflectance in all cases. Depending on the changes in window geometry and reflectance of the surfaces surrounding the treatment room, the change in the area where the standard daylighting requirements are met was analyzed. The distribution of daylight factor values in each case was also examined. Finally, the. results for the demonstrated climate zones were compared. Modelling, simulation and subsequent calculation was carried out in the Building Design program.