Stiffness degradation resulting from 90° ply cracking in [± θ n/90 m] s angle-ply composite laminates has been evaluated by a 3D finite-element method. A control volume having a single simulated transverse crack in 90° ply/plies and intact ± θ outer layers is used for the analysis. The stiffness degradation as a transverse crack extends in the width direction for glass/epoxy angle-ply laminates is calculated for different crack lengths and different fibre orientation angles θ of the outer layers. Effects of the number of 90° layers and number of ± θ layers on the laminate stiffness have also been studied. It has been observed that the available stiffness of the cracked angle-ply laminate largely depends on the fibre orientation angle of the outer layers, the number of cracked cross-ply layers and the number of uncracked outer ± θ layers in the laminate.