The 1955 constitution stated, "The Ethiopian Orthodox Church, founded in the fourth century on the doctrines of Saint Mark, is the established church of the Empire and is, as such, supported by the state." The church was the bulwark of the state and the monarchy and became an element in the ethnic identity of the dominant Amhara and Tigray. By contrast, Islam spread among ethnically diverse and geographically dispersed groups at different times and therefore failed to provide the same degree of political unity to its adherents. Traditional belief systems were strongest in the lowland regions, but elements of such systems characterized much of the popular religion of Christians and Muslims as well. Beliefs and rituals varied widely, but fear of the evil eye, for example, was widespread among followers of all religions.

Officially, the imperial regime tolerated Muslims. For example, the government retained Muslim courts, which dealt with family and personal law according to Islamic law. However, the imperial authorities gradually took over Muslim schools and discouraged the teaching of Arabic. Additionally, the behavior of Amhara administrators in local communities and the general pattern of Christian dominance tended to alienate Muslims.

The revolution brought a major change in the official status of the Ethiopian Orthodox Church and other religions. In 1975 the Mengistu regime disestablished the church, which was a substantial landholder during the imperial era, and early the next year removed its patriarch. The PMAC declared that all religions were equal, and a number of Muslim holy days became official holidays in addition to the Christian holidays already honored. Despite these changes, divisions between Muslims and Christians persisted.

Data as of 1991