There is provided an optical body with improved antireflection capability, a display device, and a method for manufacturing an optical body, the optical body including: a first concave-convex structure formed on a surface of a base material; and a second concave-convex structure superimposed on the first concave-convex structure. An average concave-convex period of the first concave-convex structure is larger than a wavelength in a visible light region, an average concave-convex period of the second concave-convex structure is less than or equal to the wavelength in the visible light region, and projecting parts of the second concave-convex structure extend in a direction normal to a flat plane of the base material.