A protective cover for lining one or more edges of an undermount sink is provided. The protective cover has a means for removably attaching the cover to one or more interior ledges of the countertop adjacent to one or more sides of the sink, and is formed of a pliable material such as vinyl. In one embodiment, the protective cover is shaped to protect the edge of the countertop adjacent to the sink, without means for attachment to the countertop.