The importance of initial {10-12} twins in the formation of deformation texture was investigated by conducting strain path change tests of rolled Mg–3Al–1Zn alloy in which {10-12} twinning dominated the deformation. The existence of initial twins changed a twinning process by preferring the growth of initial twins rather than the nucleation of new twins, which led to a non-Schmid behavior of twinning characteristics and consequently caused a completely different deformation texture compared with the counterpart without initial twins.