Motor vehicle side door comprising a box under a window part, the box comprising: - a front wall and a rear wall, a frieze reinforcement connecting the front wall in the upper part of the box with the rear wall, along the window part, - an intermediate reinforcement arranged longitudinally inside the gate box, and extending between the front wall and the rear wall, distant from the frieze reinforcement, - a support for the order of the exterior opening of the gate arranged inside the door box, between the frieze reinforcement and the intermediate reinforcement, wherein the support for the order of the exterior opening of the gate comprises zones for fixing to the frieze reinforcement and to the intermediate reinforcement, so as to be fixed on one side to the frieze reinforcement and on the other to the intermediate reinforcement, and in that the side door comprises an outer opening order comprising: - a handle, - a plate fixed to the outer opening order support, from the vehicle inner side by report to the outer opening order support, the box comprising an outer panel, the support and the outer panel each comprising an opening facing each other, the handle passing through the two openings. - a front wall and a rear wall, a frieze reinforcement connecting the front wall in the upper part of the box with the rear wall, along the window part, - an intermediate reinforcement arranged longitudinally inside the gate box, and extending between the front wall and the rear wall, distant from the frieze reinforcement, - a support for the order of the exterior opening of the gate arranged inside the door box, between the frieze reinforcement and the intermediate reinforcement, wherein the support for the order of the exterior opening of the gate comprises zones for fixing to the frieze reinforcement and to the intermediate reinforcement, so as to be fixed on one side to the frieze reinforcement and on the other to the intermediate reinforcement, - an intermediate reinforcement arranged longitudinally inside the gate box, and extending between the front wall and the rear wall, distant from the frieze reinforcement, - a support for the order of the exterior opening of the gate arranged inside the door box, between the frieze reinforcement and the intermediate reinforcement, wherein the support for the order of the exterior opening of the gate comprises zones for fixing to the frieze reinforcement and to the intermediate reinforcement, so as to be fixed on one side to the frieze reinforcement and on the other to the intermediate reinforcement, and in that the side door comprises an outer opening order comprising: - a handle, - a plate fixed to the outer opening order support, from the vehicle inner side by report to the outer opening order support, the box comprising an outer panel, the support and the outer panel each comprising an opening facing each other, the handle passing through the two openings. - a handle, - a plate fixed to the outer opening order support, from the vehicle inner side by report to the outer opening order support, the box comprising an outer panel, the support and the outer panel each comprising an opening facing each other, the handle passing through the two openings.