D-8, also known as Developing-8, is an organization for development cooperation among the following countries: Bangladesh, Egypt, Indonesia, Iran, Malaysia, Nigeria, Pakistan and Turkey.

The establishment of D-8 was announced officially through the Istanbul Declaration of Summit of Heads of State/Government on June 15, 1997.

The objectives of D-8 Organization for Economic Cooperation are to improve member states' position in the global economy, diversify and create new opportunities in trade relations, enhance participation in decision-making at international level, and improve standards of living.

D-8 is a global arrangement rather than a regional one, as the composition of its members reflects. Organization for Economic Cooperation (D-8) is a forum with no adverse impact on bilateral and multi-lateral commitments of the member countries, emanating from their membership to other international or regional organizations.

Ambassador Dato' Ku Jaafar Ku Shaari from Malaysia is currently the Secretary General of the D-8 Organization with its Secretariat based in Istanbul-Turkey.

The idea of cooperation among major Muslim developing countries was mooted by Prof. Dr. Necmettin Erbakan, the then Prime Minister of Turkey, during a Seminar on “Cooperation in Development” which was held in Istanbul in October 1996. The group envisioned cooperation among countries stretching from South East Asia to Africa. Representatives from Bangladesh, Egypt, Indonesia, Iran, Malaysia, Nigeria and Pakistan attended the Seminar. This conference was the first step towards the establishment of D-8 and it was only after a series of preparatory meetings that D-8 was set up officially and began its activities with the Istanbul Declaration issued at the end of the summit of Heads of State and Government held in Istanbul on June 15, 1997.