<p>Research on the TIG–MIG/MAG (tungsten inert gas – metal inert gas / metal active gas) hybrid welding process has grown significantly in response to industrial demands for more competitive manufacturing methods. This study evaluates how key operational parameters of a TIG–MIG/MAG hybrid welding process (TIG torch height, MIG/MAG wire extension, distance between electrodes, torch angles, and TIG current) affect the weld bead geometry (weld width, reinforcement height, penetration depth, toe angle, and dilution rate). A design of experiments combined with statistical analysis (including central composite design, response surface methodology, main effects analysis, and ANOVA) was used to identify the most influential factors and quantify their effects. The distance between electrodes emerged as the dominant factor affecting all geometry responses, with shorter distances generally increasing reinforcement and reducing dilution and toe angle. TIG current was the next most significant factor, strongly influencing weld width and penetration. Notably, high reinforcement was achieved using a short electrode spacing, lower TIG current, a moderate TIG torch height (~ 4.5&#xa0;mm), and a MIG/MAG torch angle of ~ 35°. Conversely, short penetration resulted from a low TIG current, reduced TIG torch height and electrodes distance, and a larger MIG/MAG angle. Toe angle was increased by a short electrodes distance and low TIG torch height (i.e. bringing the torches closer), combined with a MIG/MAG angle around 30°, whereas dilution was minimized with a short electrode distance and low TIG current, with an optimal MIG/MAG angle of ~ 35°. Overall, by adjusting the studied parameters within the tested range, it is possible to control and optimize weld bead geometry. The findings underscore the potential of TIG–MIG/MAG hybrid welding to be tuned for improved weld profiles, and they provide practical guidelines for process configuration.</p>