A under-counter drawer (30, 130, 230) for a table (10, 136), in particular a height-adjustable desk, comprising: - a frame that is configured as a carcass, - an extendable box, which is slidably accommodated on the frame, wherein the carcass encloses the extendable box on several sides and has flat outer sides, at least one outwardly flat lower side and an outwardly flat upper side, and wherein inner surfaces of the upper side and the lower side are provided with ribbing (118, 120), and - two or more mounting adapters (44, 46; 244, 246) for mounting the under-counter drawer (30, 130) to the underside of a tabletop (12, 138), wherein the two or more mounting adapters (44, 46; 244, 246) can be accommodated on the frame at a distance from one another such that the frame can also be mounted on the underside of the tabletop (12, 138) in the case of a crossing support (22, 126), wherein the two or more mounting adapters (44, 46; 244, 246) act as spacers between the tabletop (12, 138) and the frame, wherein a plurality of mounting positions for the two or more mounting adapters (44, 46; 244, 246) are provided on the frame, wherein through holes are formed on the frame for attachment to the tabletop (12, 138), wherein the through-holes are arranged on the right and left of the carcass in a lateral edge region, respectively, wherein the through-holes are arranged in the respective edge region between a lateral outer wall and an inwardly offset inner wall which carries a drawer runner, and wherein the extendable box is arranged between the inner walls and is mounted on a right-hand and a left-hand drawer runner. - a frame that is configured as a carcass, - an extendable box, which is slidably accommodated on the frame, wherein the carcass encloses the extendable box on several sides and has flat outer sides, at least one outwardly flat lower side and an outwardly flat upper side, and wherein inner surfaces of the upper side and the lower side are provided with ribbing (118, 120), and - two or more mounting adapters (44, 46; 244, 246) for mounting the under-counter drawer (30, 130) to the underside of a tabletop (12, 138), wherein the two or more mounting adapters (44, 46; 244, 246) can be accommodated on the frame at a distance from one another such that the frame can also be mounted on the underside of the tabletop (12, 138) in the case of a crossing support (22, 126), wherein the two or more mounting adapters (44, 46; 244, 246) act as spacers between the tabletop (12, 138) and the frame, wherein a plurality of mounting positions for the two or more mounting adapters (44, 46; 244, 246) are provided on the frame, wherein through holes are formed on the frame for attachment to the tabletop (12, 138), wherein the through-holes are arranged on the right and left of the carcass in a lateral edge region, respectively, wherein the through-holes are arranged in the respective edge region between a lateral outer wall and an inwardly offset inner wall which carries a drawer runner, and wherein the extendable box is arranged between the inner walls and is mounted on a right-hand and a left-hand drawer runner. wherein the two or more mounting adapters (44, 46; 244, 246) can be accommodated on the frame at a distance from one another such that the frame can also be mounted on the underside of the tabletop (12, 138) in the case of a crossing support (22, 126), wherein the two or more mounting adapters (44, 46; 244, 246) act as spacers between the tabletop (12, 138) and the frame, wherein a plurality of mounting positions for the two or more mounting adapters (44, 46; 244, 246) are provided on the frame, wherein through holes are formed on the frame for attachment to the tabletop (12, 138), wherein the through-holes are arranged on the right and left of the carcass in a lateral edge region, respectively, wherein the through-holes are arranged in the respective edge region between a lateral outer wall and an inwardly offset inner wall which carries a drawer runner, and wherein the extendable box is arranged between the inner walls and is mounted on a right-hand and a left-hand drawer runner.