An unstacking machine for trays and the like disposed in elevationally stacked relation providing a frame adapted to receive such a stack of trays including powered tray pick-off means mounted on the frame for reciprocal movement successively to engage the uppermost tray in the stack and to remove it laterally substantially horizontally from the stack and powered stack elevating means on the frame operative upwardly to advance the stack through successive increments of travel to position each succeeding uppermost tray in the path of movement of said pick-off means for removing the trays one at a time from the stack.