This research presents the results of tungsten inert gas (TIG) welding of aluminum alloy 1100 in the butt joint, with single pass. The sample dimensions were 100 × 50 × 3mm3. The TIG welding was done with 2.4 mm diameter filler of ER4043. Tensile and hardness tests were performed on successfully welded samples to determine the best welding parameters. In this work, a quadratic response surface model is fitted to the obtained data, using response surface methodology (RSM) to identify and analyze the interactions between the responses of controllable factors and to optimize process parameters. The main factors influencing the choice of welding are the range of the material to be welded, which is aluminum alloys, the thickness of the base materials, and the type of parameters. TIG welding is a simple and user-friendly welding procedure. This study takes into account the frequently used aluminum AA1100 alloy in order to optimize the process parameters. By taking into account the key influencing process parameters such as welding current, root gap, and gas flow rate with 18 experimental runs and 5 levels, the response surface methodology with central composite design as the design of experiment was used. The results were analyzed using design expert statistical software. The analysis was performed using these parameters, and the responses, tensile strength and hardness, were obtained to provide the best results. The experiment shows that the desirable parameter among the solutions was attained, with the best values being current of 118.44 Amp, root gap of 1 mm, and gas flow rate of 8 L/min, with a desirability of 0.879. These parameters can be used to achieve better hardness and tensile properties of the welded metal. Keywords: RSM, Central composite design, Aluminum1100, TIG welding parameters, Alternative current, parametric optimization, Mechanical properties,