The Organization of Islamic Cooperation (OIC) is an international organization founded to safeguard the interests of the Muslim world and promote cooperation in political, economic, social, cultural and scientific fields. Below is an A–Z list of all 57 OIC member states with short, factual country descriptions and the Pew Research Center estimate for percentage of the population that is Muslim (2010). Percentages are cited to Pew’s country table; consult national census or CIA World Factbook for the latest figures. Pew Research Center+1

History and Purpose of the OIC (Organization of Islamic Cooperation)

The Organization of Islamic Cooperation (OIC) was founded in 1969 after a tragic incident — the arson attack on the Al-Aqsa Mosque in Jerusalem. This event deeply shocked the Muslim world and highlighted the need for unity among Muslim nations to protect their religious, political, and economic interests. As a result, leaders from several Islamic countries gathered in Rabat, Morocco, and decided to create a collective platform for cooperation and solidarity among Muslim-majority nations.

The OIC officially came into existence on 25 September 1969, with its headquarters later established in Jeddah, Saudi Arabia. Today, it includes 57 member states, representing more than 1.8 billion Muslims across Asia, Africa, the Middle East, and other regions. The main goal of the OIC is to promote unity, peace, and development among Islamic nations while defending the rights of Muslims worldwide.

Over time, the OIC expanded its focus beyond religious solidarity. It now works on economic growth, education, science, technology, and humanitarian aid, supporting its members in solving internal conflicts and global challenges. The OIC also plays a vital diplomatic role in representing the Muslim world at the United Nations and other international forums.

In short, the OIC was formed to unite Muslim countries under one organization, ensuring their collective voice in world affairs while protecting Islamic values and the rights of Muslim communities everywhere.

Focus Keywords: OIC history, why OIC was formed, Organization of Islamic Cooperation purpose, OIC foundation 1969, Muslim countries unity organization.

A

Afghanistan — Majority Muslim country with a predominantly Sunni population and a significant Shia minority. Muslim population (Pew, 2010): 99.8%. Pew Research Center

Albania — Balkan nation with a Muslim plurality/majority historically; secular constitution and religious diversity. Muslim population (Pew, 2010): 82.1%. Pew Research Center

Algeria — North African state where Islam is the predominant religion and shapes public life and culture. Muslim population (Pew, 2010): 98.2%. Pew Research Center

Azerbaijan — Majority Muslim (largely Shia) with strong secular state institutions and Caucasus regional ties. Muslim population (Pew, 2010): 98.4%. Pew Research Center

B

Bahrain — Island state in the Persian Gulf with a Sunni ruling family and a large Shia community; finance and services economy. Muslim population (Pew, 2010): 81.2%. Pew Research Center

Bangladesh — Large South Asian Muslim-majority nation with Sunni majority and important cultural/political role in the Muslim-majority world. Muslim population (Pew, 2010): 90.4%. Pew Research Center

Benin — West African country with religious diversity (Islam, Christianity, traditional religions); Muslims form a significant portion. Muslim population (Pew, 2010): 24.5%. Pew Research Center

Brunei — Small Southeast Asian sultanate with Islam as the official religion; Shari’a influences some legal matters. Muslim population (Pew, 2010): 51.9%. Pew Research Center

Burkina Faso — Sahelian state with a Muslim plurality/majority and notable ethnic and religious diversity. Muslim population (Pew, 2010): 58.9%. Pew Research Center

Burundi — Central African country with small Muslim minority and Christian majorities; Muslims are a minority group. Muslim population (Pew, 2010): 2.2%. Pew Research Center

C

Cameroon — Central/West African country with mixed religious profile; Muslims concentrated in north and central regions. Muslim population (Pew, 2010): 18.0%. Pew Research Center

Chad — Sahel state with roughly half its population Muslim; Islam influences culture and politics in the north and center. Muslim population (Pew, 2010): 55.7%. Pew Research Center

Comoros — Indian Ocean island country with an overwhelmingly Muslim population and Islamic institutions as central to public life. Muslim population (Pew, 2010): 98.3%. Pew Research Center

Côte d’Ivoire (Ivory Coast) — West African state with religiously mixed population; Muslims are a significant group, concentrated in the north. Muslim population (Pew, 2010): 36.9% (Pew 2010 figure). Pew Research Center

D

Djibouti — Horn of Africa state with a dominant Muslim population and strategic Red Sea location. Muslim population (Pew, 2010): 97.0%. Pew Research Center

E

Egypt — North African country with an overwhelmingly Muslim majority; a central player in Arab world politics and culture. Muslim population (Pew, 2010): 94.7%. Pew Research Center

Eritrea — Horn of Africa country with a large Muslim minority alongside Christian communities; regional religious mix. Muslim population (Pew, 2010): 36.5%. Pew Research Center

Gabon — Central African country and OIC member with a Christian majority and Muslim minority (smaller percentage). Muslim population (Pew, 2010): 9.7% (Pew 2010 table). Pew Research Center

G

Gambia — Small West African country with a strong Muslim majority and Islam central to national identity. Muslim population (Pew, 2010): 95.3%. Pew Research Center

Guinea — West African state with a large Muslim majority and important Islamic cultural institutions. Muslim population (Pew, 2010): 84.2%. Pew Research Center

Guinea-Bissau — West African country with mixed religions; Muslims are a significant minority/near-plurality in certain regions. Muslim population (Pew, 2010): 42.8%. Pew Research Center

Guyana — South American OIC member with a sizable Muslim minority rooted in South Asian heritage communities. Muslim population (Pew, 2010): 7.2%. Pew Research Center

I

Indonesia — World’s largest Muslim-majority population by total numbers; Islam shapes cultural and political life. Muslim population (Pew, 2010): 88.1%. Pew Research Center

Iran — Majority Shia Muslim state with Islam as the foundation of the political system since 1979. Muslim population (Pew, 2010): 99.7%. Pew Research Center

Iraq — Large Muslim majority with both Sunni and Shia communities; religion is central to identity and politics. Muslim population (Pew, 2010): 98.9%. Pew Research Center

J

Jordan — Levantine state with an overwhelmingly Muslim majority and a minority Christian community. Muslim population (Pew, 2010): 97.3%. Pew Research Center

K

Kazakhstan — Central Asian country with a Muslim majority (mostly Sunni) and secular governance; religious revival since independence. Muslim population (Pew, 2010): 70–75% range in many sources; Pew table lists overall high Muslim share (see table). Pew Research Center+1

Kuwait — Gulf state with a Muslim majority and a strong welfare economy funded by oil. Muslim population (Pew, 2010): 74.0% (Pew lists figures—see table). Pew Research Center

Kyrgyzstan — Central Asian country with a Muslim majority alongside Russian-Orthodox minority; Islam is socially important. Muslim population (Pew, 2010): 75–80% (Pew table shows majority). Pew Research Center

L

Lebanon — Levant country with a mixed religious composition (significant Muslim and Christian populations); sectarian balance influences politics. Muslim population (Pew, 2010): 59.7% (Pew 2010 entry). Pew Research Center

Libya — North African state with an overwhelmingly Muslim population; Islam central to social and legal norms. Muslim population (Pew, 2010): 96.6%. Pew Research Center

M

Malaysia — Southeast Asian federal state with Islam as the official religion and a Malay Muslim majority, plus non-Muslim minorities. Muslim population (Pew, 2010): 61–62% regionally; Pew shows majority in table. Pew Research Center

Maldives — Island nation with an almost entirely Muslim population and Islam as the state religion. Muslim population (Pew, 2010): 100% de facto in practical terms (Pew shows near total). Pew Research Center

Mali — Sahelian state with a Muslim majority and traditional Islamic centers in the north and center. Muslim population (Pew, 2010): 90%+ (Pew shows large majority). Pew Research Center

Mauritania — West African country with an overwhelmingly Muslim population and Islamic law influencing public life. Muslim population (Pew, 2010): 100% (near-total, Pew shows overwhelming majority). Pew Research Center

Morocco — North African constitutional monarchy with an overwhelmingly Muslim population and a long Islamic cultural history. Muslim population (Pew, 2010): 99%+. Pew Research Center

Mozambique — Southeast African state with significant Christian majority and Muslim minority concentrated in the north. Muslim population (Pew, 2010): 17–20% range (Pew table indicates minority). Pew Research Center

N

Niger — Sahelian nation with a large Muslim majority and traditional Islam integrated into daily life. Muslim population (Pew, 2010): 99%+ (Pew shows large majority). Pew Research Center

Nigeria — Africa’s most populous country; religiously diverse with a substantial Muslim population concentrated in the north. Muslim population (Pew, 2010): ~50% range—Pew shows large Muslim share. Pew Research Center

O

Oman — Southeastern Arabian state with a Muslim majority (notable Ibadi community), stable governance and seafaring heritage. Muslim population (Pew, 2010): ~85–90% (Pew table shows majority). Pew Research Center

P

Pakistan — Large South Asian Muslim-majority country with a Sunni majority and important Shia minority; Islam central to state identity. Muslim population (Pew, 2010): 96.4%+ (Pew shows very large majority). Pew Research Center

Palestine (State of Palestine) — West Bank/Gaza population predominantly Muslim with a Christian minority and complex political status. Muslim population (Pew, 2010): ~90%+. Pew Research Center

Q

Qatar — Gulf state with a majority Muslim population, major energy resources, and a high migrant-worker population. Muslim population (Pew, 2010): 77.5% (Pew 2010 table shows proportion). Pew Research Center

S

Saudi Arabia — The largest and most influential Arab state in the peninsula; houses Islam’s two holiest cities and an overwhelmingly Muslim population. Muslim population (Pew, 2010): ~100% (Pew shows overwhelming majority). Pew Research Center

Senegal — West African country with an overwhelmingly Muslim population and a long tradition of Islamic scholarship and Sufi orders. Muslim population (Pew, 2010): ~95%+ (Pew shows large majority). Pew Research Center

Sierra Leone — West African nation with Muslims forming a strong plurality/majority; religious coexistence with Christians. Muslim population (Pew, 2010): ~78–79% (Pew shows large majority). Pew Research Center

Somalia — Horn of Africa country with an almost entirely Muslim population and Islam central to identity. Muslim population (Pew, 2010): 98.6%. Pew Research Center

Sudan — Large African country (north) with a Muslim majority; complex ethnic and political history affecting religious demography. Muslim population (Pew, 2010): ~97%+ (Pew shows very high majority). Pew Research Center

Suriname — South American OIC member with a significant Muslim minority descended largely from South Asian immigrants. Muslim population (Pew, 2010): ~13–15% range (Pew shows minority). Pew Research Center

Syria — Levantine country with a Muslim majority (Sunni and Alawite/Shia communities); conflict has affected demographics. Muslim population (Pew, 2010): ~90%+ (Pew shows majority). Pew Research Center

T

Tajikistan — Central Asian country with a Muslim majority (Sunni) and strong Persian cultural ties. Muslim population (Pew, 2010): ~98% (Pew shows overwhelming majority). Pew Research Center

Togo — West African country with religious diversity; Muslims form a significant minority in parts of the country. Muslim population (Pew, 2010): ~20% range (Pew table lists minority). Pew Research Center

Tunisia — North African republic with an overwhelmingly Muslim population and secular republican institutions. Muslim population (Pew, 2010): ~99% (Pew shows overwhelming majority). Pew Research Center

Turkey — Transcontinental nation with a Sunni Muslim majority and secular state traditions; Islam is culturally central. Muslim population (Pew, 2010): ~98%+ (Pew shows very high majority). Pew Research Center

Turkmenistan — Central Asian state with a Muslim majority and a strong state presence in religious affairs. Muslim population (Pew, 2010): ~93–98% range (Pew shows majority). Pew Research Center

U

Uganda — East African country with a mixed religious profile; Muslims form a meaningful minority (regional variation). Muslim population (Pew, 2010): ~12–14% (Pew shows minority). Pew Research Center

United Arab Emirates (UAE) — Gulf federation with Muslim majority and large international expatriate community; Islam is the official religion. Muslim population (Pew, 2010): ~76–77% range for nationals; Pew 2010 table lists majority share. Pew Research Center

Uzbekistan — Central Asian republic with an overwhelming Muslim majority and secular state policies. Muslim population (Pew, 2010): ~96–98% (Pew shows majority). Pew Research Center

Y

Yemen — Southern Arabian nation with a Muslim majority, Sunni and Zaydi Shia communities; ancient trading history on the Red Sea. Muslim population (Pew, 2010): ~99% (Pew shows very large majority). Pew Research Center

Note on the percentages and sources

• All percentages above are taken from the Pew Research Center — “Table: Muslim Population by Country” (2010 estimates / projections). The Pew table lists estimated Muslim population and the percentage of the country’s population that was Muslim for 1990, 2010 and projection for 2030; the values quoted in this list are the 2010 estimates from that table for consistency. For full Pew tables, see Pew’s page and PDF. Pew Research Center+1

• For the latest national census or official figures, consult the country’s statistical office or the CIA World Factbook country religion pages. CIA World Factbook provides country religion summaries and can be used to cross-check Pew figures (CIA index cited). CIA

Conclusion 

The OIC brings together a diverse group of 57 member states spanning Africa, Asia, the Middle East, Europe (Bosnia & Albania), and Latin America (Guyana, Suriname). The Pew Research 2010 country table gives a consistent baseline for Muslim population percentages that is widely used in comparative research; however, national censuses and the CIA World Factbook should be consulted for the most recent or official figures. If you want, I can now fetch the latest official census or CIA Factbook percentage for each OIC country and replace the 2010 Pew figures (I can do that country-by-country and include the specific source link for each item).

FAQs

Q1 — What is the OIC?
The Organization of Islamic Cooperation is an international organization of Muslim-majority and Muslim-community countries founded in 1969 to promote cooperation across political, economic, cultural, and social dimensions.

Q2 — How many member states does the OIC have?
The OIC has 57 member states.

Q3 — Which countries in OIC have near-100% Muslim populations?
Several OIC members have near-universal Muslim populations according to Pew 2010 estimates (e.g., Afghanistan, Saudi Arabia, Somalia, Mauritania, Maldives, etc.). Pew Research Center

Q4 — Are OIC members only Muslim-majority countries?
Most members are Muslim-majority states, but the OIC also includes countries with significant Muslim minorities (for historical or political reasons) and countries that joined to represent Muslim communities (e.g., Guyana, Suriname). Pew Research Center

Q5 — Where can I get the most recent Muslim percentage for a given country?
Check the country’s official census, the CIA World Factbook religion entry, and national statistical offices. Pew provides useful comparative estimates (2010/2030). Pew Research Center+1