The optimization of spatial planning in order to identify the most suitable places for the installation of wind farms is one of the most difficult problems mainly due to the need of identification and calculation of a variety of qualitative and quantitative parameters as well as their effect on the final solution. Multi Criteria Decision Making Methods (MCDM) are commonly used in order to solve this problem and are combined with Geographic Information Systems (GIS) to spatially represent the results from the application of the MCDM methodology. This paper presents a methodology which is based on the combination of a MCDM methodology called Analytical Hierarch Process (AHP) and GIS in order to determine the most suitable locations for wind farms installation. The calculated locations are then ranked using the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) in order to rank the locations based on installation suitability. The application of this methodology can help decision makers to easily overcome conflicting parameters and propose optimal solutions which are acceptable from citizens and stake holders while at the same time are economical and environmental friendly.