A Classification of Ontology Change Giorgos Flouris (1,2) Dimitris Plexousakis (2) Grigoris Antoniou (2) 1 Istituto della Scienza e delle Tecnologie della Informazione, C.N.R., Via G. Moruzzi, 1, 56124, Pisa, Italy georgios.flouris@isti.cnr.it 2 Institute of Computer Science, FO.R.T.H. P.O. Box 1385, GR 71110, Heraklion, Greece {fgeo, dp, antoniou}@ics.forth.gr Abstract The problem of modifying an ontology in response to a certain need for change is a complex and multifaceted one, being addressed by several different, but closely related and often overlapping research disciplines. Unfortunately, the boundaries of each such discipline are not clear, as certain terms are often used with different meanings in the relevant literature. The purpose of this paper is to identify the exact relationships, connections and overlaps between these research areas and determine the boundaries of each field, by performing a broad review of the relevant literature.