The present application relates to a control surface for an aircraft. The control surface has a leading edge, a trailing edge, and a chord-line defined between the leading edge and the trailing edge. A first aerodynamic surface is between the leading and trailing edges and a second surface is between the leading and trailing edges. The leading edge is formed by a nose, the nose having a hinge axis about which the control surface is deflectable. A maximum thickness of the control surface perpendicular to the chord-line between the first aerodynamic surface and the second surface is located aft of the hinge axis. The present application also relates to a control surface for an aircraft having a maximum curvature of the first aerodynamic surface of the control surface located aft of the hinge axis. The present application also relates to an aircraft or part of an aircraft comprising a fixed section and a control surface.