Abstract: A jig for coping crown molding includes a base with a pair of right-angled isosceles triangular support blocks mounted on dowels to the base and with their faces that are at a 45.degree. incline to the base normally facing forward on the base. In one embodiment, the base has a rod which mounts one or more clamps. The clamps hold a length of crown molding with one of its flat rear surfaces resting on the base and with its inclined flat rear surface against the inclined faces of the support blocks. An end of the crown molding piece projects beyond the base where it is accessible for hand coping. The proper shape of the end of the crown molding for corner junctions can then be achieved using wholly vertical saw strokes. In another embodiment, the crown molding is held against the inclined surfaces of the support blocks by an abutment that is adjustably positioned on the base and spaced from the support blocks.