A unit for grouping packages along a transfer path includes an input station receiving the packages arranged in longitudinal lines parallel to the transfer path; an output station for groups defined by a given number of packages from respective longitudinal lines and aligned in at least one line crosswise to the transfer path; a movable conveying surface, which is fed at predetermined time intervals with a number of packages equal to that of each group, and feeds the packages along the transfer path; and at least one movable member, which is fed cyclically along an operating path having at least one portion parallel to the transfer path, and has an aligning surface, against which, at each cycle, the packages in each group upstream from the movable member come to rest and are aligned in at least one line crosswise to the transfer path; the movable member also has a push surface which, at each cycle, acts on each group of packages downstream from the movable member to push the group out of the unit.