Disclosed is a pallet aligning system which allows a pallet to be mounted to a pallet support arm in a desired orientation and lateral spacing with respect to the support arm and thereafter be removed and remounted to the support arm in the previously defined orientation and lateral spacing, thereby precluding the need to reposition the pallet upon each subsequent reattachment thereof to a pallet support arm. This pallet alignment system is particularly useful when combined with a screen alignment system to re-establish registration of the screens as well as the pallets used therewith. Lateral restraining members are mounted to the underside of the pallet for selective laterally movement. After the pallet has been oriented and positioned as desired, the lateral restraining members are moved into abutment against opposite lateral sides of the pallet support arm and secured in their respective positions thereat to maintain the set orientation and location of the pallet. When the pallet is removed, the lateral restraining members remain mounted stationarily to the underside of the pallet in their set positions so that upon remounting of the pallet to the support arm, the restraining members serve to orient and locate the pallet in the previously established position, thereby eliminating the need to reestablish the desired positioning of the pallet upon each subsequent reattachment to a pallet support arm. The pallet aligning system is particularly useful to remount a pallet in a centered position with respect to an image on a screen of a screen printing head used to print an image from edge-to-edge on a workpiece such as a T-shirt.