A side sill assembly for a vehicle includes an inner shell connected to an outer shell and a reinforcement assembly. The reinforcement assembly includes a longitudinally extending tube and a plurality of reinforcement brackets provided at longitudinally spaced locations along the length of the tube. The reinforcement brackets each include a front wall and a back wall connected by an outer side wall. The reinforcement brackets define recesses for receiving the tube that is welded to the front walls and the back walls where the tube contacts an edge of the recesses. The reinforcement brackets may include a top flange on a top edge and a base flange on a bottom edge of each of the front walls and back walls. An inner flange is provided on an inner edge of each of the front walls and back walls that is welded to the inner shell.