The Arab League, whose annual summit opens in Qatar on Tuesday, represents some 367 million people in 22 countries, but Syria's membership was suspended in 2011 over its brutal response to protests.
The pan-Arab bloc was created in Cairo on March 22, 1945. It comprises Algeria, Bahrain, Comoros, Djibouti, Egypt, Iraq, Kuwait, Jordan, Lebanon, Libya, Mauritania, Morocco, Oman, Qatar, Saudi Arabia, Somalia, Sudan, Syria, Tunisia, the United Arab Emirates, Yemen and Palestine, currently represented by the Palestinian Authority.
The Arab League has had its headquarters in Cairo, with the exception of an 11-year gap when member states decided to move it to Tunis to punish Egypt for having signed a separate peace treaty with Israel in 1979.
The League is governed by a charter signed in 1945 and a joint defence and economic cooperation treaty signed in 1950.
Its main objective is to "consolidate links between its member states and to coordinate their policies with a view to ensuring cooperation between them and preserve their independence and their sovereignty".
It is supposed to achieve "cooperation between the member countries in the economic, financial, cultural and social domains".
In January, Arab leaders meeting in Riyadh pledged to remove obstacles to finalising a free trade zone this year and agreed to facilitate capital flows.
The League's decision-making body is its Council, which is made up of representatives of the member states, whether heads of state or government, or ministers. The supreme body is the Arab summit, which takes decisions by unanimity and meets once a year.
The first Arab summit was held in January 1964, and recognised the necessity of the creation of a Palestinian entity.
The League's secretary generals are traditionally drawn from the country that hosts its headquarters. Egypt's Nabil al-Arabi succeeded his compatriot Amr Mussa in May 2011, for a five-year term.
The League voted at an extraordinary meeting in November 2011 to suspend Syria until President Bashar al-Assad implements an Arab peace plan that requires him to step down.
On March 6, the League said it would be prepared to hand Syria's seat to the opposition National Coalition if it sets up an executive body, but League officials said the coalition's election of Ghassan Hitto as interim prime minister on Tuesday might not go far enough.