Abstract: A disposable cat litter box liner formed of flexible sheet material, preferably paper, is adapted to assume a generally flat configuration prior to use, a generally box-shaped configuration upon insertion into a cat litter box for holding litter therein, and a generally bag-shaped configuration upon removal from the litter box for disposing of the litter therein. The liner includes an arrangement of fold lines associated with the end panels for permitting the liner to be folded into a generally flat configuration prior to use. The liner includes a pair of elongate opposite top panels, which can advantageously include handles to facilitate lifting of the liner. When the top panels are clasped together and the liner lifted thereby with cat litter in the receptacle, the bottom panel collapses downward, the side panels collapse inward, and the liner assumes a generally bag-shaped configuration for disposal of cat litter therein.