56 Members (excluding the associate or suspended members but including the countries represented on their behalf) [The rulers are not necessarily the representatives in the organisation. ] :
| | UNITED ARAB EMIRATES | (Abu Dhabi ar) | | President Sheikh Muhammad bin Zayed Al Nahyan | | |
| | AFGHANISTAN | (Dushanbe x) | | Amrullah Saleh | | |
| | ALBANIA | (Tirana) | | President Ilir Meta | | |
| | AZERBAIJAN | (Baku) | | President Iham Aliyev | | |
| | BANGLADESH | (Dhaka a) | | President Abdul Hamid | | |
| | BURKINA FASO | (Ouagadougou) | | President Paul-Henri Sandaogo Damiba | | |
| | BAHRAIN | (Manamah) | | King Sheikh Hamad bin Isa Al Khalifah | | |
| | BENIN | (Porto Novo a + Cotonou ilnqr) | | President Patrice Talon | | |
| | BRUNEI DARUSSALAM | (Bandar Seri Begawan) | | Sultan Hassanal Bolkiah | | |
| | COTE D´IVOIRE | (Yamoussoukro a + Abidjan dln + Cocody b) | | President Alassane Ouattara | | |
| | CAMEROON | (Yaounde) | | President Paul Biya | | |
| | DJIBOUTI | (Djibouti) | | President Ismail Omar Guelleh | | |
| | ALGERIA | (Algiers a + El Biar d + El Mouradia r) | | State President Abdelmadjid Tebboune | | |
| | EGYPT | (Cairo a + Alexandria r + Almasa New Capital City f) | | President Abdel Fattah el-Sisi | | |
| | GABON | (Libreville) | | President Ali Ben Bongo Ondimba | | |
| | THE GAMBIA | (Banjul) | | President Adama Barrow | | |
| | GUINEA | (Conakry) | | Mamady Doumbouya | | |
| | GUINEA-BISSAU | (Bissau) | | President Umaro Sissoco Embalo | | |
| | GUYANA | (Georgetown) | | President Mohamed Irfaan Ali | | |
| | INDONESIA | (Jakarta a + Nusantara f + Bogor r + Chipanas r + Yogyakarta r + Tampaksiring r) | | President Joko Widodo | | |
| | IRAQ | (Baghdad) | | President Barham Salih | | |
| | IRAN | (Tehran) | | Supreme Leader Ayatollah Ali Khamenei | | |
| | JORDAN | (Amman) | | King Abdullah II | | |
| | KYRGYZSTAN | (Bishkek) | | President Sadyr Zhaparov | | |
| | COMOROS | (Moroni) | | President Azali Assoumani | | |
| | KUWAIT | (Kuwait City) | | Emir Sheikh Nawaf Al Ahmad Al Jabir Al Sabah | | |
| | KAZAKHSTAN | (Nur-Sultan a) | | President Kasym-Zhomart Tokayev | | |
| | LEBANON | (Beirut a + Baabda r + Hadeth d) | | President Michel Aoun | | |
| | LIBYA | (Tripoli a) | | Muhammad Younus Al-Menfi | | |
| | MOROCCO | (Rabat a) | | King Muhammad VI | | |
| | MALI | (Bamako) | | Assimi Goita | | |
| | MAURITANIA | (Nouakchott) | | President Mohamed Ould Ghazouani | | |
| | MALDIVES | (Male) | | President Ibrahim Mohamed Solih | | |
| | MALAYSIA | (Putrajaya aj + Kuala Lumpur ejlry) | | Sultan Abdullah Shah | | |
| | MOZAMBIQUE | (Maputo) | | President Filipe Nyusi | | |
| | NIGER | (Niamey) | | President Mohamed Bazoum | | |
| | NIGERIA | (Abuja a) | | President Muhammadu Buhari | | |
| | OMAN | (Muscat) | | Sultan Haitham bin Tarik | | |
| | PAKISTAN | (Islamabad) | | President Arif Alvi | | |
| | PALESTINE | (Ramallah qr + (East Jerusalem)) | | President Mahmoud Abbas | | |
| | QATAR | (Doha) | | Emir Sheikh Tamim bin Hamad Al Thani | | |
| | SAUDI ARABIA | (Riyadh) | | King Salman | | |
| | SUDAN | (Khartoum) | | Abdel-Fatah al-Burhan Abdelrahman | | |
| | SIERRA LEONE | (Freetown) | | President Julius Maada Wonie Bio | | |
| | SENEGAL | (Dakar) | | President Macky Sall | | |
| | SOMALIA | (Mogadishu-Hamar Weyne) | | President Hassan Sheikh Mohamud | | |
| | SURINAME | (Paramaribo) | | President Chan Santokhi | | |
| | CHAD | (Ndjamena) | | President Mahamat Idriss Deby Itno Kaka | | |
| | TOGO | (Lome) | | President Faure Gnassingbe | | |
| | TAJIKISTAN | (Dushanbe) | | President Emomali Rakhmonov | | |
| | TURKMENISTAN | (Ashgabat) | | President Serdar Berdymukhammedov | | |
| | TUNISIA | (Tunis a + Bardois df) | | President Kais Saied | | |
| | TURKIYE | (Ankara a + Marmaris s) | | President Recep Tayyip Erdogan | | |
| | UGANDA | (Kampala a + Entebbe r) | | President Yoweri Museveni | | |
| | UZBEKISTAN | (Tashkent a) | | Shavkat Mirziyayev | | |
| | YEMEN | (Riyadh x) | | Rashad al-Alimi | | |