Abstract: An anti-derailment device for lift or elevator door leaves (2), of the type provided with at least one guide shoe (4) at the lower or upper end thereof, suitable for sliding in a groove (5) formed in a lower sill (6) of the door or defined in an upper recess of the door, is characterised in that it comprises an element (9), associated with the shoe (4) or with the leaf (2), which is shaped like a hook so as to interact with at least one bent edge (11) of the groove (5), hooking thereto in response to a stress on the leaf (2) which tends to produce a derailment of the shoe (4).