This paper constitutes a theoretical study of the aerodynamic forces on an oscillating or steady wing of finite span moving forward at a uniform supersonic speed. The treatment is based on the linearized theory obtained by considering only small disturbances in an ideal fluid. The wing is therefore considered to be a nearly flat thin surface at a small angle of attack and the flow is considered non- viscous and free of strong shocks. The theory in this case is equivalent to finding certain solutions of the wave equation in three dimensions with respect to a moving coordinate system.