Purpose: The paper presents the effect of the laser welding parameters of the laser focal position, the welding speed and the laser output power on the weldability of Al the 5052 alloy during laser lap welding. Design/methodology/approach: Lap welding is conducted on an Al 5052 plate with a thickness of 1 mm. After welding, the bead surfaces and cross sections were evaluated with various laser welding parameters. The degree of porosity was also examined by X-ray transmission testing. Findings: The influences of the focal point, the laser power and the welding speed on the formation of bead and on the degree of porosity were experimentally investigated. The bead quality was improved when the beam was defocused compared to when it was focused on the surface. It was found that the porosity decreased when the heat input is lowered, except when the lower plate is not melted. Research limitations/implications: Various types of aluminium alloys, such as sheet, extrusion and casting types, are used industrially in diverse combinations. Therefore, it is necessary to evaluate the weldabilities of these materials. This research is limited to Al 5052 alloys at present plans are underway to expand it to various aluminium based alloys. Practical implications: Automotive industries are continuously increasing their use of aluminium alloys in manufacturing. The results of this research can be referred to by the automotive industry as a basic technique. Originality/value: This research shows the influence of different welding parameters on the weldability during the lap welding of Al 5052 Al alloy. The results are based on the extensive experiments.