The article analyzes the role of ideology in building a postcolonial order in the Arab world. Ideology traditionally plays a significant role in the formation of public policy, both foreign and domestic. The formation of the ideological system and its subsequent influence on political processes began after the collapse of the Ottoman Empire in the early 20th century. The intensified pan-Islamic and pan-Arab tendencies led to national liberation wars and the formation of sovereign states. However, the actual colonial dependence of the countries of the Arab world on the West persisted, which reflected the impossibility of the development and implementation of pan-Arab ideas. In general, pan–Islamic and pan-Arab ideas did not help to get rid of colonial dependence, but became an important basis for the formation of post-colonial ideologies – Arab nationalism and Islamism. The process of decolonization entered an active phase only after the Second World War. The post-war movement of Arab nationalism partially contributed to the formation of a post-colonial order in the Arab world. The subsequent ideological system in the form of Islamism did not get rid of the colonial legacy, however, laid the foundation for post-Islamism, which demonstrated its potential after the Arab Spring.