Axial dislocations and other imperfections in single‐crystal whiskers of aluminum nitride (hexagonal, wurtzite structure) have been studied by transmission electron microscopy. Axial dislocations withcBurgers vectors and faults on the (101¯0) prismatic planes having fault vectors equal to ½chave been identified. In addition to simple axial dislocations, the variety of axial imperfections included zig‐zagged dislocations and wide periodic imperfections attributed to complicated faults, clearly related to the dislocation with acBurgers vector.One type of AlN whisker with growth direction ⟨c+2a⟩ always contained an axial dislocation or the related extended defect, and it is thus concluded that the growth of this type of whisker may have involved an axial dislocation.