State membership, Date of membership and Status
- Iran September 1960 Founder Member
- Iraq September 1960 Founder Member
- Kuwait September 1960 Founder Member
- Saudi Arabia September 1960 Founder Member
- Venezuela September 1960 Founder Member
- Qatar December 1960 Full Member
- Libya December 1962 Full Member
- Indonesia December 1962 Full Member
- United Arab Emirates November 1967 Full Member
- Algeria July 1969 Full Member
- Nigeria July 1971 Full Member
- Ecuador* November 1973 Full Member
- Gabon December 1973 Associate Member
* Ecuador left OPEC in 1992 (1412/13 AH).
