A respirator mask liner is provided for positioning between a respirator mask and the face of a wearer. The mask liner includes a flexible sheet material having an outer perimeter edge portion and a hole that is spaced inwardly from the outer perimeter edge portion. At least one tab projects outwardly from portions of the perimeter edge portion, and may be unitarily formed with the sheet material. The mask liner is configured so that when it is to be placed between the face of the wearer and the respirator mask, the tab or tabs project outwardly beyond the gasket portion of the respirator mask, so that the tabs may be used for adjusting the liner or securing the liner to the mask. Optionally, the mask liner has a surface texture with a ribbed and undulating pattern of raised portions, and/or incorporates an anti-microbial substance.