| Name: | Organization of Petroleum Exporting Countries (OPEC) |
| Foundation date: | 14 September 1961 |
| Headquarters: | Vienna (Austria) |
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OPEC flag |
| 14 September 1961 | Iran, Iraq, Kuwait, Saudi Arabia, Venezuela |
| 15 January 1962 | Qatar |
| 5 April 1962 | Indonesia |
| 4 June 1962 | Libya |
| 27 November 1967 | Abu Dhabi (9 January 1974 membership succeeded to the United Arab Emirates) |
| 8 July 1969 | Algeria |
| 10 July 1971 | Nigeria |
| 27 June 1973 | Ecuador |
| 9 June 1975 | Gabon |
