Friction Stir Welding (FSW) is a relatively new process which has proved to be a much more viable joining process for all Aluminium Alloys than earlier techniques, such as Metal Inert Gas, Tungsten Inert Gas, Laser Welding and Resistance Welding. Friction Stir Welding is the fastest evolving joining technology and the principal prospective technique for implementing integral fuselage structure in aircraft manufacturing. Friction Stir Welding is a solid-state joining process that uses a non-consumable tool to join two facing work pieces without melting the work piece material. The main objective of the work is to study the effect of mechanical properties like Hardness, Tensile strength along with Microstructure by varying the tool rotational speed of 500 rpm, 710 rpm, 1000 rpm and 1400 rpm during the Friction Stir Welding of Aluminium Alloy 6082 with different reinforcement percentages of 5%, 10% and 15% of Aluminium Oxide (Al2O3). FSW process parameters were optimized using the ANOVA method and Response Surface Methodology to determine the optimum values of Tensile strength of the joints.