 This study examined the effect of tool pin eccentricity and welding speed on the microstructure, texture and mechanical properties of friction stir welded aluminum alloy AA5754H24. It was found that increasing the welding speed from 100 to 500 millimeters per minute decreased the average grain size of the nugget zone from 18, 15 and 18 microns at 0, 0.2 and 0.8 millimeters eccentricity, respectively, to 12.4, 10 and 11 microns, respectively. Additionally, increasing the welding speed from 100 to 500 millimeters per minute also improved the tensile strength of the welded joints, which was attributed to the increase in the number of dislocations and the decrease in the amount of voids in the welded joints. Furthermore, the yield stress of the welded joints increased from 35 MPa to 40 MPa when the welding speed was increased from 100 to 500 millimeters per minute. This article was authored by Mohamed M. Z. Ahmed, Ahmed R. S. Essa, Sabah Ataya and others.