A method for aligning rectangular packaging boxes comprising the steps of: conveying packaging boxes along a transport path in a conveying direction by means of a conveying device, wherein the conveying device comprises a first conveying unit and a second conveying unit opposite the first conveying unit, the first conveying unit and the second conveying unit defining the transport path, wherein the first conveying unit and the second conveying unit each comprise at least one belt (30, 32) receiving and jointly conveying the packaging boxes between them; and aligning each packaging box of the conveyed packaging boxes, which comprise a distortion in a way that at least some side surfaces of the packaging box are not oriented perpendicularly to each other, by means of at least one stop element arranged in the area of the conveying device, wherein aligning each packaging box comprises: arranging the at least one stop element in a first position, in which the at least one stop element projects into the transport path, wherein the at least one stop element is arranged stationarily in the first position; conveying the packaging box against the at least one stop element, wherein the conveying device continues to move in the conveying direction relative to the at least one stop element and thus forces the packaging box against the at least one stop element, until each section of the packaging box facing the at least one stop element rests against the at least one stop element and the side surfaces of the packaging box are oriented perpendicularly to each other, wherein at least one stop site (82, 84) of the at least one stop element against which the packaging box comes to rest defines a plane which is oriented perpendicularly to the conveying direction; moving the at least one stop element out of the first position and into a second position when each section of the packaging box facing the at least one stop element rests against the at least one stop element, wherein the at least one stop element, when in the second position, does not project into the transport path, and thus releasing the aligned packaging box for further transport in the conveying direction. conveying packaging boxes along a transport path in a conveying direction by means of a conveying device, wherein the conveying device comprises a first conveying unit and a second conveying unit opposite the first conveying unit, the first conveying unit and the second conveying unit defining the transport path, wherein the first conveying unit and the second conveying unit each comprise at least one belt (30, 32) receiving and jointly conveying the packaging boxes between them; and aligning each packaging box of the conveyed packaging boxes, which comprise a distortion in a way that at least some side surfaces of the packaging box are not oriented perpendicularly to each other, by means of at least one stop element arranged in the area of the conveying device, wherein aligning each packaging box comprises: arranging the at least one stop element in a first position, in which the at least one stop element projects into the transport path, wherein the at least one stop element is arranged stationarily in the first position; conveying the packaging box against the at least one stop element, wherein the conveying device continues to move in the conveying direction relative to the at least one stop element and thus forces the packaging box against the at least one stop element, until each section of the packaging box facing the at least one stop element rests against the at least one stop element and the side surfaces of the packaging box are oriented perpendicularly to each other, wherein at least one stop site (82, 84) of the at least one stop element against which the packaging box comes to rest defines a plane which is oriented perpendicularly to the conveying direction; moving the at least one stop element out of the first position and into a second position when each section of the packaging box facing the at least one stop element rests against the at least one stop element, wherein the at least one stop element, when in the second position, does not project into the transport path, and thus releasing the aligned packaging box for further transport in the conveying direction. arranging the at least one stop element in a first position, in which the at least one stop element projects into the transport path, wherein the at least one stop element is arranged stationarily in the first position; conveying the packaging box against the at least one stop element, wherein the conveying device continues to move in the conveying direction relative to the at least one stop element and thus forces the packaging box against the at least one stop element, until each section of the packaging box facing the at least one stop element rests against the at least one stop element and the side surfaces of the packaging box are oriented perpendicularly to each other, wherein at least one stop site (82, 84) of the at least one stop element against which the packaging box comes to rest defines a plane which is oriented perpendicularly to the conveying direction; moving the at least one stop element out of the first position and into a second position when each section of the packaging box facing the at least one stop element rests against the at least one stop element, wherein the at least one stop element, when in the second position, does not project into the transport path, and thus releasing the aligned packaging box for further transport in the conveying direction.