The Chapel of the Tablet at theChurch of Our Lady Mary of Zionallegedly houses the original Ark of the Covenant.

Most residents in the Horn of Africa practice one of the three major Abrahamic faiths, religions that have an ancient presence in the region.

Engraving of the ancient Fakr ad-Din Mosque in Mogadishu built in 1269.

Ancient Axum produced coins and stelae associated with the disc and crescent symbols of the deity Ashtar. Axum became one of the earliest states to adoptChristianity following the conversion of King Ezana II in the 4th Century C.E. Islam's relationship with the region began when Bilal ibn Rabah or Bilal al-Habeshi a person of Ethiopian Habeshaorigin (born in Mecca c578 / 582) was chosen by the Islamic prophet Muhammad to be the first muezzin.

The history of commercial and intellectual contact between the inhabitants of the Somali coast and the Arabian Peninsula may help explain the Somali people's connection with Muhammad. Early on, a band of persecuted Muslims had, at the Muhammad's urging, fled across the Red Sea into the Horn of Africa. There, the Muslims were granted protection by the Ethiopian negus (king). Islam may thus have been introduced into the Horn of Africa well before the faith even took root in its place of origin.

Judaism also has a long presence in the region, most notably in the form of the Beta Israel community. Southern Ethiopia in particular is also home to many varieties of indigenous belief systems, such as the Sura people's acknowledgment of the deity Tumu.