A simplified structure for a wing skin and wing box wherein the internal surface (2) of an aircraft wing skin panel (1) in the wing box includes a multiplicity of strips (3), each strip being associated with a stringer. The strips (3) have different gradients in the span-wise direction S, which is the direction in which the strips extend. The surface of each strip is, in the chord-wise direction C, parallel to the external surface (5). At a junction, at which a rib meets a stringer, the interior surface (2) has an area (4a) that is parallel to the exterior surface (5), such that the rib and stringer at that junction may be simply attached to the wing skin panel (1).