The Arab Socialist Ba'ath Party, commonly known as the Ba'ath Party, is a pan-Arab socialist political movement founded in 1947 in Syria by Michel Aflaq, Salah al-Din al-Bitar, and associates of Zaki al-Arsuzi. It espouses Ba'athism, an ideology blending Arab nationalism, pan-Arabism, Arab socialism, and anti-imperialism, aiming for the unification of the Arab world into a single state. The party's motto, 'Unity, Freedom, Socialism,' emphasizes Arab unity, liberation from non-Arab influence, and socialist principles. The organizational structure was formalized at the 2nd National Congress in 1954 through amendments to its Internal Regulations. Initially merged from earlier Ba'ath groups in the 1940s, the party gained prominence in Syria and Iraq, promoting secularism and class struggle against traditional elites like landowners and industrialists.

The Ba'ath Party experienced a significant split in 1966 into Syrian- and Iraqi-dominated factions, leading to parallel organizations. The Syrian branch, under Hafez al-Assad from 1970 to 2000 and subsequently his son Bashar al-Assad, has ruled Syria since 1963 through an authoritarian, secular framework as the vanguard party, advocating socialist policies and Arab nationalism. The Iraqi faction, led by Saddam Hussein, held power from 1968 until 2003, with its regional branch established in 1972. Both factions have been criticized for authoritarianism, human rights abuses, and suppression of dissent, though they promoted pan-Arab unity and anti-imperialist stances.

Despite its ideological roots in socialism and nationalism, the Ba'ath Party's governance in Syria and Iraq has been marked by centralized control, cult of personality under leaders like the Assads and Hussein, and involvement in regional conflicts. The Syrian branch remains in power amid ongoing civil war, while the Iraqi branch was dismantled after the 2003 U.S. invasion. The party continues to influence Arab politics through its emphasis on secularism and resistance to Western interference, though its pan-Arab unification goals remain unfulfilled.