This study focused on the multi-response optimization of friction stir welding (FSW) process for an optimal parametric combination to yield favorable tensile strength and elongation using the Taguchi based Grey relational analysis (GRA). The objective functions have been selected in relation to parameters of FSW parameters; rotating speed, welding speed and tool shoulder diameter. The experiments were planned using Taguchi's L-8 orthogonal array. Multi-response optimization was applied using Grey relation analysis and Taguchi approach to solve the problem. The significance of the factors on overall quality characteristics of the welding process has also been evaluated quantitatively by the analysis of variance (ANOVA) method. Optimal results have been verified through confirmation experiments. This study has also showed the application feasibility of the Grey relation analysis in combination with Taguchi technique for continuous improvement in welding quality.