Assembly for an aircraft having a wing and an engine pylon for mounting a jet engine beneath said wing, the engine pylon having: - a primary structure forming a box and having a starboard-side lateral panel, a port-side lateral panel, an upper spar, a lower spar and a rear rib that closes the box at the rear, - a first and a second set of upper shackles (252, 254), wherein the first set of upper shackles fastens, in use, the starboard-side lateral panel to a structural element of the wing, and wherein the second set of upper shackles fastens, in use, the port-side lateral panel to a structural element of the wing, - a first and a second set of lower shackles (260, 262), wherein the first set of lower shackles fastens, in use, the starboard-side lateral panel to a structural element of the wing, and wherein the second set of lower shackles fastens, in use, the port-side lateral panel to a structural element of the wing, - a fastening element secured to either the rear rib or the lower spar, - a rear rod that connects the fastening element to a structural element of the wing, and - a transverse shackle that connects the upper spar to a structural element of the wing, wherein the line connecting the two centres of the transverse shackle is oriented transversely with respect to a longitudinal axis of the engine pylon, - a reinforcing panel (280a-d), at each join between a starboard-side or port-side lateral panel (208a-b) and a shackle of the first or second set of upper or lower shackles (252, 254, 260, 262), which is fastened along the height against the starboard-side or port-side lateral panel (208a-b) and to which said shackle of the first or second set of upper or lower shackles (252, 254, 260, 262) is also fastened. - a primary structure forming a box and having a starboard-side lateral panel, a port-side lateral panel, an upper spar, a lower spar and a rear rib that closes the box at the rear, - a first and a second set of upper shackles (252, 254), wherein the first set of upper shackles fastens, in use, the starboard-side lateral panel to a structural element of the wing, and wherein the second set of upper shackles fastens, in use, the port-side lateral panel to a structural element of the wing, - a first and a second set of lower shackles (260, 262), wherein the first set of lower shackles fastens, in use, the starboard-side lateral panel to a structural element of the wing, and wherein the second set of lower shackles fastens, in use, the port-side lateral panel to a structural element of the wing, - a fastening element secured to either the rear rib or the lower spar, - a rear rod that connects the fastening element to a structural element of the wing, and - a transverse shackle that connects the upper spar to a structural element of the wing, wherein the line connecting the two centres of the transverse shackle is oriented transversely with respect to a longitudinal axis of the engine pylon, - a reinforcing panel (280a-d), at each join between a starboard-side or port-side lateral panel (208a-b) and a shackle of the first or second set of upper or lower shackles (252, 254, 260, 262), which is fastened along the height against the starboard-side or port-side lateral panel (208a-b) and to which said shackle of the first or second set of upper or lower shackles (252, 254, 260, 262) is also fastened.