Friction stir welding (FSW) of aluminium alloys became increasingly important across many industries, where the welded joints are required to have acceptable structural and functional properties. Conventional single-side FSW (SS-FSW), particularly, in thick-section joints, leads frequently to a reduction in weld properties, because of excessive heat input. Double-side friction stir welding (DS-FSW) has arisen as a potential solution to mitigate these limitations by balancing the thermal cycles and improving joint properties. In the present work, DS-FSW is executed on AA7075-T651 10 mm thick plates, and the resulting joints are evaluated methodically for wear performance with the help of a pin-on-disc wear testing setup. The microstructural features and precipitate morphology are also evaluated through optical microscopy and transmission electron microscopy. The DS-FSW joints exhibit superior wear performance, as evidenced by lesser friction coefficients and reduced specific wear rates, in comparison with both the base material and SS-FSW joints. Metallurgical characterization shows that the weld nugget of DS-FSW contained fine equiaxed grains, accompanied by significant reprecipitation of strengthening phases following their dissolution during welding. The combined effects of grain refinements and enhanced retaining of hardening precipitates are identified as the primary contributors to the improved wear resistance of DS-FSW joints. Overall, the findings establish DS-FSW as an effective technique for improving the wear properties of high-strength aluminium-alloy welds, chiefly in thick-section applications.