The inelastic behaviour during unloading In an AZ31B Mg alloy sheet was Investigated under various loading paths from both macroscopic and microscopic points of view. In-plane cyclic loading-unloading tests were carried out under monotonic tension and compression, tension followed by compression and compression followed by tension, and the transition of Instantaneous gradient during unloading was examined. Metallographic observation was then carried out to investigate the effect of the activation of the twinning on the inelastic behaviour during unloading. The inelastic behaviour was more pronounced when the twinning was activated, i.e., under monotonic compression, tension followed by compression, and the detwinning process during compression followed by tension. The results showed that the activation of twinning has a great effect on the inelastic behaviour during unloading. © 2011 Wiley-VCH Verlag GmbH & Co. KGaA. Weinheim.