The invention relates to an assembly for an aircraft comprising a wing element (2) and a suspension pylon (4) for an engine (10) under the wing element, the suspension pylon (4) comprising a rigid structure (6) forming a box provided with an aft closing element (28), and the wing element (2) having a forward spar (34) extending substantially parallel to a leading edge (30) of the wing element. According to the invention, the rigid structure is assembled on the wing element such that the aft closing element bears in contact with the forward spar (34).