Triple lines in polycrystalline aggregates are lines where three grains meet. It is shown that these lines can be interpreted as disclinations if the relations between adjoining grain orientations are chosen as nearest-neighbour relations. These relations are needed for describing quantitatively the structure of the individual boundaries as dislocation networks. The disclination character of the triple line decides the dislocation balance between the adjoining boundaries, and so may imply differences in the physical character of different triple lines.
