Suomen Operaatiotutkimusseura ry
- Finnish OR society.
- http://www.optimointi.fi/

The Operational Research Society - Study Groups & Regional Societies
- Details of news, forthcoming presentations and study materials of regional branches of the society.
- http://www.orsoc.org.uk/region/study/infor.htm

ORBEL
- Begian Operations Research Society - proposes an agenda of conferences as well as teaching information on O.R.
- http://www.orbel.be

Operational Research Society of New Zealand
- Membership, meetings, resources.
- http://www.esc.auckland.ac.nz/Organisations/ORSNZ/

Australian Society for Operations Research (ASOR)
- Membership, meetings, resources.
- http://www.asor.ms.unimelb.edu.au/

Operational Research Society of Singapore
- Membership, meetings, jobs, resources.
- http://sunsite.nus.edu.sg/ORSS/

Aðgerðarannsóknafélag Íslands
- Icelandic Operations Research Society (ICORS).
- http://www.hi.is/~snjolfur/orsociety.htm

Dansk Selskab for Operationsanalyse
- Danish OR society.
- http://www.dorsnet.dk/

ORSSA
- South African OR society.
- http://www.orssa.org.za/

S.E.I.O.
- Spanish OR society.
- http://www.cica.es/aliens/seio/

AIRO
- Italian Society of Operations Research, Optimization and Decision Science. Includes membership, meetings, and publications.
- http://www.airo.org/

Hungarian Operations Research Society
- Publications, meetings, jobs and other resources.
- http://www.hors.hu/

Gesellschaft für Operations Research e. V.
- German OR society.
- http://www.gor-ev.de/

Operational Research Society
- United Kingdom OR society.
- http://www.orsoc.org.uk/

Netherlands Society for Statistics and Operational Research
- VVS: Vereniging voor Statistiek en Operationele Research / Netherlands Society for Statistics and Operations Research.
- http://www.vvs-or.nl/english/indexenglish.htm

ROADEF
- French OR society.
- http://www.roadef.org/

Canadian Operational Research Society/Société Canadienne de Recherche Opérationnelle
- Bulletin, meetings, careers, membership information and other resources. French and English site.
- http://www.cors.ca/

INFORMS
- Institute for Operations Research and the Management Sciences. American OR society.
- http://www.informs.org/