The invention relates to a haul truck body, comprising a front wall and two opposing side walls. Each side wall presenting an inner surface and an upper edge portion extending rearwardly from a rear end of side wall towards the front wall. Also, each side wall presents an upper reinforcement element which is integrally formed with the side wall and extends along the upper edge portion of the side wall. The invention also relates to a truck and a method for manufacturing a haul truck body.