Agro-climatic zonation is a classification technique that uses several meteorological and topographical data of our targeted region for proper zonation with higher priority towards crop suitability factors. This study deals with creating such zonation using 7 major factors for the entire state of Tamil Nadu using GIS and AHP. The Agro-climatic variables include precipitation, evapotranspiration, land surface temperature, land use and land cover data, soil moisture, soil order and ground water level. On incorporating the data in GIS with attribute tables, thematic maps were created through inverse distance weighting interpolation. Such maps were over-laid so that zoning using all the defined factors could be made feasible. Weightage given for each factor was determined based on Analytical Hierarchy Process, with precipitation and soil order with the highest priority. A final map was obtained with Agro-climatic zones defined based on the degree of suitability for agriculture from highest to lowest. This classification can further help to define the suitability of various crops on a region and can help in planning an appropriate crop pattern for that region.