You have to create your QPolygon points in the order that you would see them if you started walking at one vertex of your polygon and walked around the outside edge. As you reach each new vertex, add it to the list of points. Since Qt is mostly a 2-D coordinate system, it does not matter which way you walk around the polygon. In a 3-D system (like OpenGL), it does matter because if you walk in one direction you are defining the front face of the polygon, and it you walk the other way, it defines the back face. So if you intend to do 3-D graphics some day, pick the direction that defines a front-facing walk.