The European Journal of Operational Research (EJOR) is a peer-reviewed academic journal in operations research.

It was founded in 1977[1] by the Association of European Operational Research Societies,[2] and is published by Elsevier, with Roman Słowiński as its Co-ordinating Editor.

It is a top journal (CABS 4; ABDC A*) and the primary journal for Europe-based studies of operations research.

It is the world's largest operations research journal.

[4] 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 operations research, and modeling and simulation.