A wing tip device for fixing to the outboard end of a wing (401), the wing (401) defining a wing plane, the wing tip device comprising: an upper wing-like element (404) projecting upwardly with respect to the wing plane and having a trailing edge (416); and a lower wing-like element (407) fixed with respect to the upper wing-like element (404) and having a root chord and a trailing edge (417), the lower wing-like element (407) root chord intersecting with the upper wing-like element (404), and the lower wing-like element (407) projecting downwardly from the intersection, wherein the upper wing-like element (404) is larger than the lower wing-like element (407) and the trailing edge (417) of the lower wing-like element is adjacent the trailing edge (416) of the upper wing-like element at the intersection, and wherein an included angle between the upper and lower wing-like elements (404, 407) at the intersection is less than, or equal to, 160 degrees. Also, a wing with the wing tip device; an aircraft with the wing; a method of fitting, or retro-fitting, the wing tip device to a wing; a method of modifying an existing wing tip device; and a method of operating a wing with the wing tip device.