Abstract This study compares the deformation and fracture behavior of a basal-textured Mg AZ31 alloy sheet under uniaxial tension and biaxial stretching by using an in-plane biaxial test setup capable of observing and measuring the deformation at both meso (millimeter) and microstructure scales. Strain distributions at the mesoscale and accompanying fracture surfaces indicate a significant dependence on strain path. At the microscale, limited slip activity in biaxial case promotes contraction twins, where severe strain localizations (emax/emean ≈ 20) to the twins and their boundaries cause mainly transgranular fracture. This leads to a brittle, and a more pronounced shear-type fracture under biaxial stretching. In uniaxial case, considerable tensile twinning activity reorients the initial texture for slip activity. Strain localizations (emax/emean ≈ 2) to the grain interiors and boundaries initiate mainly intergranular fracture. Samples fail by displaying both brittle and ductile fracture structures, with smaller shear lips compared to the biaxial case.