Abstract: Ladder assemblies are needed on large vehicles for an operator to ascend to the cab of a vehicle. The ladder assembly should be moveable between a lowered position for easy access and a raised position to prevent damage to the ladder when the vehicle is in use. The subject ladder assembly includes a pair of spaced rails mounted to the vehicle and an elongate ladder moveably positioned between the spaced rails. Cooperating means extend between the rails and the elongate ladder to position the ladder with respect to the rails and guide the ladder on the rails when the ladder is moved. The arrangement of components provides a simple and compact arrangement for raising and lowering the ladder.