The invention relates to an aircraft engine assembly (1) including an engine (6) and an engine mounting device (4), the mounting device being designed to be inserted between a wing of the aircraft and the engine, and comprising a rigid structure (8) and means of mounting the engine onto the rigid structure, the mounting means comprising a forward fastener (10) and an aft fastener (12). According to the invention, the aft fastener comprises two aft half-fasteners (12a) that will each resist at least the forces applied along a longitudinal direction (X) of the engine, and the two aft half-fasteners are arranged so that a horizontal plane (P) passing through a longitudinal axis (5) of the engine passes through each of them.