A manipulator for use with a lift truck includes a guide assembly mountable on a mast of a lift truck, a carriage assembly supported for movement along the guide assembly, and an arm assembly mounted on the carriage assembly for supporting a lift truck attachment such as a clamping apparatus. The arm assembly may include two arms pivotable with respect to each other about a substantially vertical axis. The manipulator can move a load in a widthwise direction of a lift truck and between opposite widthwise sides of a lift truck.