A manually-operated tray assembly for facilitating the handling of transparencies on an overhead projector. The tray assembly comprises a dispensing tray for holding a stack of transparencies prior to projection, and a receiving tray for accepting the transparencies following projection. The transparencies are slid one-at-a-time from the dispensing tray to the platen of the projector, and following projection, from the platen to the receiving tray by a stroke of the user's hand. The `used` transparencies accumulate in the receiving tray in a neat orderly stack. The dispensing tray is preferably arranged at a sloping angle relative to the platen of the projector so that only one transparency at a time is transferred to the platen. The receiving tray is also preferably arranged at a sloping angle relative to the platen to facilitate the transfer of transparencies from the platen to the receiving tray. The dispensing tray and the receiving tray are preferably located on the same side of the projector and are held in suitable positions relative to the projector to accommodate the transfer of transparencies to and from the platen. The user retains complete control over the transparency while it is located on the platen of the projector and may move it about on the platen as desired.