Wind tunnel experiments and numerical simulations (CFD) were carried out on gable-roof buildings with different roof slopes. Experimental studies were implemented in wind tunnel on roof models with three different slopes (alpha = 10 degrees, alpha = 20 degrees, and alpha = 30 degrees). Database was created around the building for time-averaged velocity, turbulent kinetic energy, and pressure coefficient. Analyses were implemented for investigations of grid number effect and turbulence model effect for the alpha = 20 degrees roof slope model. Grid determination and turbulence models were investigated and validated by comparing the results of the computational fluid dynamics simulations with the experimental data for all the roof slopes. Generally, the numerical results showed compatibility with the experimental results despite some differences. Eventually, the effect of the roof slope on the gable-roof buildings were expressed using the computational fluid dynamics results.