The effect of welding parameters on the mechanical properties of friction stir-welded dissimilar aluminium alloys in overlap joint configuration was studied. Both the welding configuration and the materials chosen were a typical skin-stringer configuration, widely used for aeronautical fuselage panels. Mechanical properties were evaluated by means of both hoop stress and T-pull test. Results show that there is a great dependence of the hoop stress resistance from welding parameters; conversely, T-pull tests do not show the same dependence. The present work demonstrates the suitability of the x in lap configuration for joining dissimilar aluminium alloys. Copyright © 2013 John Wiley & Sons, Ltd.