A cup (6) for spray guns, comprising a disposable container (8) joined in removable fashion to a lid (5) with axial outflow fitting (7), independent of the cup and integrated with the body (4) of the gun (1), and a lining element (18) whose shape is complementary to that of the lid (5) and which is inserted in removable fashion within said lid (5) between the container (8) and the outflow fitting (7).