The harmful effects of traditional methods of power generation on the environment has created a need to strategically plan and develop renewable and sustainable energy generation systems. This paper presents the wind farm site suitability analysis using multi-criteria decision making (MCDM) approach based on geographic information system (GIS) modeling. This analysis is based on different climatic, economic, aesthetic and environmental criteria like wind resource, accessibility by roads, proximity to the electrical grid, and optimum/safe distance from various settlements and airports. Using information from published literature, criteria constraints like buffer zones, exclusion zones and suitability scores for each criteria is developed. An analytical hierarchy process, AHP is employed to assign appropriate weights to the criteria according to their relative importance. The developed model is then applied to the entire Kingdom of Saudi Arabia. The most suitable sites are found to be (i) near Ras Tanura on the coast in the Eastern Province; (ii) Turaif in Al-Jawf region at northern borders and (iii) Al-Wajh on the coast in the western region. The central and southeastern region is found to be unsuitable mainly due to scarce wind resource, few settlements and less connectivity by roads and electrical grid.