The structure and configuration of threading dislocations (TDs) in AlN films grown on (0001) sapphire by metal–organic vapor phase epitaxy (MOVPE) were characterized by high-resolution transmission electron microscopy (HRTEM). It was found that the TDs formed in the films were mainly the perfect edge dislocations with the Burgers vector of b = ⅓〈11¯20〉. The majority of the edge TDs were not randomly formed but densely arranged in lines. The arrays of the edge TDs were mainly observed on the {11¯20} and {10¯10} planes. These two planes showed different configurations of TDs. TD arrays on both of these planes constituted low-angle boundaries. We suggest that these TDs are introduced to compensate for slight misorientations between the subgrains during the film growth.