A dispensing system (e.g., in a warehouse or other item-fulfillment environment) can include a tray holder sized for releasably receiving a tray. A rotational actuator may operate to pivot the tray holder between a first position aligned for receipt in the tray holder of a tray in a recumbent orientation and a second position in which the tray is arranged in an upended orientation. When the tray is in the upended orientation, an opening system may engage a door on an end of the tray to move the door from a closed state in which items contained in the tray are prevented from falling out of the tray and to an open state in which the items are allowed to fall out of the tray.