Friction Stir Spot Welding (FSSW) is a recent welding technique used for spot welding of thin sheets. Response surface methodology (RSM) is used to develop a model for the tensile shear failure load of AA6061joined by FSSW. The experiments are conducted for different combinations of three parameters viz. tool rotational speed, dwell time and shoulder diameter as per Box -Behnken design and mathematical model is developed. The developed equation is used to find the optimum parameter combinations for obtaining joints with higher TSFL. © 2006-2016 Asian Research Publishing Network (ARPN). All rights reserved.