A process for assembling aircraft control surfaces (1, 1′), in particular high-lift devices and wing portions, allows implementing smooth control surfaces in short times, wherein the control surface is defined by an upper skin (2) and by a lower skin (9), the upper skin being destined to form the leading edge (4) of the control surface by means of the connection to a front spar (3), wherein the upper skin and the lower skin are made of a laminar composite material which, not yet hardened, is fastened to structural elements (3, 5, 6, 7) of the control surface by means of an adhesive; and wherein the resin of the composite material and the adhesive are hardened simultaneously in autoclave.