In the welding of dissimilar aluminum alloys, the success of the process primarily depends on the chemical composition and mechanical properties of the base materials. In addition, welding of aluminum alloys is highly complex due to factors such as differences in thermal conductivity, the possibility of hydrogen gas porosity during solidification, and the tendency for hot cracking. Therefore, in order to improve the weld performance of aluminum material pairs with different compositions (dissimilar alloys), it is necessary to evaluate innovative welding techniques such as friction stir welding (FSW) as well as the associated welding parameters. In this research, aluminum materials (Al5083 and Al6061) were joined using friction stir welding at two different feed rates (50 and 100 mm/min), three different spindle speeds (1000, 1500, and 2000 rpm), and three different pin geometries (triangular, square, and cylindrical). Tensile tests and microhardness measurements were conducted to evaluate the weld quality. Temperature measurements were carried out to examine the effect of temperature variations during friction stir welding. Additionally, images from the weld zone and surface roughness measurements were obtained to interpret the relationship between welding parameters and weld quality. As a result, the highest weld strengths were determined as 126.5 MPa for the cylindrical pin geometry (1000 rpm and 50 mm/min), 197 MPa for the square pin geometry (2000 rpm and 100 mm/min), and 212.5 MPa for the triangular pin geometry (2000 rpm and 50 mm/min). Surface roughness values ranged between 1.7 mu m and 5.5 mu m. Moreover, the sample with the highest weld strength (212.5 MPa) exhibited a surface roughness of 3.72 mu m. This indicates that processing parameters directly influence surface roughness. Overall, it was concluded that selecting the appropriate processing parameters (feed rate and rotational speed) and tool geometry (shoulder and pin) is of great importance for achieving adequate weld quality in friction stir welding.