A wing tip device for fixing to the outboard end of a wing (301), the wing (301) defining a wing plane, the wing tip device comprising: an upper wing-like element (304) projecting upwardly and having a trailing edge; and a lower wing-like element (307) fixed with respect to the upper wing-like element (304) and having a root chord and a trailing edge, the lower wing-like element root chord intersecting with the upper wing-like element (304), and the lower wing-like element (307) projecting downwardly from the intersection, wherein the upper wing-like element (304) is larger than the lower wing-like element (307) and the trailing edge of the lower wing-like element is adjacent the trailing edge of the upper wing-like element at the intersection, and wherein an included angle between the upper and lower wing-like elements at the intersection is less than, or equal to, 160 degrees, and wherein the lower wing-like element (307) has an element planform area less than approximately 25% of the upper wing-like element planform area, and 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.