Floor panel for forming a floor covering, wherein this floor panel is at least composed of a substrate; wherein the floor panel, on at least one pair of opposite edges, comprises coupling parts, which coupling parts allow that two of such floor panels can be coupled to each other by means of a downward movement of one floor panel in respect to the other floor panel; wherein these coupling parts, in the coupled condition of two of such floor panels, form a first locking system, which effects a locking in a first direction perpendicular to the plane of the floor panels, and form a second locking system, which effects a locking in a second direction perpendicular to the edges and in the plane of the floor panels.