A paint tray liner system and method uses a paint tray and a paint tray liner. The paint tray liner is a sheet of flexible material with an adhesive layer disposed on one side. The adhesive removably adheres the flexible sheet to the inside surface of the paint tray, so as to form a barrier between liquid paint in the tray and the inside surface of the tray. After use, the liner is peeled away from the paint tray and discarded with any paint or paint residue that remains, substantially reducing the need to clean the paint tray.