Surface treatment preparation plays a key role in the strength of adhesive joints, particularly in single-lap joints. The most optimal surface conditions must be reached to achieve a strong joint. This research aims to achieve the maximum shear strength of single-lap Al/composite joints using the laser surface treatment. Four different parameters are considered, namely power, speed, the energy density of the laser on both adherends, and the laser hatch distance (HD). To predict the strength of the connection, the Design of Experiment method has been used. Several single-lap specimens with different surface parameters were created and analyzed experimentally. The results show that the hatch distance had the greatest effect on the shear strength of the specimens, followed by the mutual impact of the Al laser surface treatment power on the HD, the mutual effect of the speed of laser in Al surface treatment on the HD, and the laser power in Al surface treatment and the speed of Al laser surface treatment had the greatest effect on strength. Additionally, it was found that there is no direct or inverse relationship between the speed and laser power parameters. The optimal design obtained has a laser surface treatment speed of 1000 mm/s and 1200 mm/s, and laser power of 18 and 9 watts for Al and composite, respectively, and 50 micrometers for HD. The obtained optimal specimen has an average shear strength and failure force of 8.6 MPa and 6.676 kN, respectively, which shows about 102% improvement compared to the sandpaper method.