The European Journal of Operational Research (EJOR) is a peer-reviewed academic journal in operational research. It was founded in 1977 by the Association of European Operational Research Societies, and is published by Elsevier, with Roman Sà Âowià Âski as its Co-ordinating Editor-in-Chief. Currently, it publishes at a rate of 24 issues per annual volume, with approximately 250 pages per issue.
It is a top journal (CABS 4; ABDC A*) and the primary journal for Europe-based studies of operational research. It is the world's largest operational research journal. For most years since 1999 it has been ranked by SCImago Journal Rank as a top-quartile journal in information systems and management, management science and operational research, and modelling and simulation.