The influence of the asymmetric rolling process (ASR) and thickness reduction on the microstructure and mechanical propertiesof Al–Mg–Si alloys is studied. The specimens of the ASR and higher thickness reduction show higher strength (both theultimate tensile strength and yield strength) and lower elongation (El). However, both the strength and El are reduced withthe increase of the rotation speed ratio (ω1/ω2) in the specimens treated by the ASR. The grain size, density of dislocations,volume fraction of deformation texture and number density of precipitates are the main reasons causing the difference instrength and El. The increment in strength is mainly due to the increase of deformation texture, density of dislocations duringthe cold rolling and number density of precipitates formed during subsequent ageing. The reduction of volume fractionof deformation texture and number density of precipitates are responsible for the decrease of the strength in the specimenstreated by the ASR. The high-density dislocations in turn provide little room for the accumulation of dislocations and thereforereduces the EI.